Screen is a full-screen window manager that multiplexes a physical
terminal between several processes (typically interactive shells).
Each virtual terminal provides the functions of a DEC VT100 terminal
and, in addition, several control functions from the ISO 6429 (ECMA
48, ANSI X3.64) and ISO 2022 standards (e.g. insert/delete line and
support for multiple character sets). There is a scrollback history
buffer for each virtual terminal and a copy-and-paste mechanism that
allows moving text regions between windows.
When screen is called, it creates a single window with a shell in it
(or the specified command) and then gets out of your way so that you
can use the program as you normally would. Then, at any time, you
can create new (full-screen) windows with other programs in them
(including more shells), kill existing windows, view a list of
windows, turn output logging on and off, copy-and-paste text between
windows, view the scrollback history, switch between windows in
whatever manner you wish, etc. All windows run their programs
completely independent of each other. Programs continue to run when
their window is currently not visible and even when the whole screen
session is detached from the user's terminal. When a program
terminates, screen (per default) kills the window that contained it.
If this window was in the foreground, the display switches to the
previous window; if none are left, screen exits. Shells usually
distinguish between running as login-shell or sub-shell. Screen runs
them as sub-shells, unless told otherwise (See "shell" .screenrc
command).
Everything you type is sent to the program running in the current
window. The only exception to this is the one keystroke that is used
to initiate a command to the window manager. By default, each
command begins with a control-a (abbreviated C-a from now on), and is
followed by one other keystroke. The command character and all the
key bindings can be fully customized to be anything you like, though
they are always two characters in length.
Screen does not understand the prefix "C-" to mean control, although
this notation is used in this manual for readability. Please use the
caret notation ("^A" instead of "C-a") as arguments to e.g. the
escape command or the -e option. Screen will also print out control
characters in caret notation.
The standard way to create a new window is to type "C-a c". This
creates a new window running a shell and switches to that window
immediately, regardless of the state of the process running in the
current window. Similarly, you can create a new window with a custom
command in it by first binding the command to a keystroke (in your
.screenrc file or at the "C-a :" command line) and then using it just
like the "C-a c" command. In addition, new windows can be created by
running a command like:
screen emacs prog.c
from a shell prompt within a previously created window. This will
not run another copy of screen, but will instead supply the command
name and its arguments to the window manager (specified in the $STY
environment variable) who will use it to create the new window. The
above example would start the emacs editor (editing prog.c) and
switch to its window. - Note that you cannot transport environment
variables from the invoking shell to the application (emacs in this
case), because it is forked from the parent screen process, not from
the invoking shell.
If "/etc/utmp" is writable by screen, an appropriate record will be
written to this file for each window, and removed when the window is
terminated. This is useful for working with "talk", "script",
"shutdown", "rsend", "sccs" and other similar programs that use the
utmp file to determine who you are. As long as screen is active on
your terminal, the terminal's own record is removed from the utmp
file. See also "C-a L".

Before you begin to use screen you'll need to make sure you have
correctly selected your terminal type, just as you would for any
other termcap/terminfo program. (You can do this by using tset for
example.)
If you're impatient and want to get started without doing a lot more
reading, you should remember this one command: "C-a ?". Typing
these two characters will display a list of the available screen
commands and their bindings. Each keystroke is discussed in the
section "DEFAULT KEY BINDINGS". The manual section "CUSTOMIZATION"
deals with the contents of your .screenrc.
If your terminal is a "true" auto-margin terminal (it doesn't allow
the last position on the screen to be updated without scrolling the
screen) consider using a version of your terminal's termcap that has
automatic margins turned off. This will ensure an accurate and
optimal update of the screen in all circumstances. Most terminals
nowadays have "magic" margins (automatic margins plus usable last
column). This is the VT100 style type and perfectly suited for
screen. If all you've got is a "true" auto-margin terminal screen
will be content to use it, but updating a character put into the last
position on the screen may not be possible until the screen scrolls
or the character is moved into a safe position in some other way.
This delay can be shortened by using a terminal with insert-character
capability.

Screen has the following command-line options:
-a include all capabilities (with some minor exceptions) in each
window's termcap, even if screen must redraw parts of the
display in order to implement a function.
-A Adapt the sizes of all windows to the size of the current
terminal. By default, screen tries to restore its old window
sizes when attaching to resizable terminals (those with "WS" in
its description, e.g. suncmd or some xterm).
-c file
override the default configuration file from "$HOME/.screenrc"
to file.
-d|-D [pid.tty.host]
does not start screen, but detaches the elsewhere running screen
session. It has the same effect as typing "C-a d" from screen's
controlling terminal. -D is the equivalent to the power detach
key. If no session can be detached, this option is ignored. In
combination with the -r/-R option more powerful effects can be
achieved:
-d -r Reattach a session and if necessary detach it first.
-d -R Reattach a session and if necessary detach or even create it
first.
-d -RR Reattach a session and if necessary detach or create it. Use
the first session if more than one session is available.
-D -r Reattach a session. If necessary detach and logout remotely
first.
-D -R Attach here and now. In detail this means: If a session is
running, then reattach. If necessary detach and logout
remotely first. If it was not running create it and notify
the user. This is the author's favorite.
-D -RR Attach here and now. Whatever that means, just do it.
Note: It is always a good idea to check the status of your
sessions by means of "screen -list".
-e xy
specifies the command character to be x and the character
generating a literal command character to y (when typed after
the command character). The default is "C-a" and `a', which can
be specified as "-e^Aa". When creating a screen session, this
option sets the default command character. In a multiuser
session all users added will start off with this command
character. But when attaching to an already running session,
this option changes only the command character of the attaching
user. This option is equivalent to either the commands
"defescape" or "escape" respectively.
-f, -fn, and -fa
turns flow-control on, off, or "automatic switching mode". This
can also be defined through the "defflow" .screenrc command.
-h num
Specifies the history scrollback buffer to be num lines high.
-i will cause the interrupt key (usually C-c) to interrupt the
display immediately when flow-control is on. See the "defflow"
.screenrc command for details. The use of this option is
discouraged.
-l and -ln
turns login mode on or off (for /etc/utmp updating). This can
also be defined through the "deflogin" .screenrc command.
-ls [match]
-list [match]
does not start screen, but prints a list of pid.tty.host strings
identifying your screen sessions. Sessions marked `detached'
can be resumed with "screen -r". Those marked `attached' are
running and have a controlling terminal. If the session runs in
multiuser mode, it is marked `multi'. Sessions marked as
`unreachable' either live on a different host or are `dead'. An
unreachable session is considered dead, when its name matches
either the name of the local host, or the specified parameter,
if any. See the -r flag for a description how to construct
matches. Sessions marked as `dead' should be thoroughly checked
and removed. Ask your system administrator if you are not sure.
Remove sessions with the -wipe option.
-L tells screen to turn on automatic output logging for the
windows.
-Logfile file
By default logfile name is "screenlog.0". You can set new
logfile name with the "-Logfile" option.
-m causes screen to ignore the $STY environment variable. With
"screen -m" creation of a new session is enforced, regardless
whether screen is called from within another screen session or
not. This flag has a special meaning in connection with the `-d'
option:
-d -m Start screen in "detached" mode. This creates a new session
but doesn't attach to it. This is useful for system startup
scripts.
-D -m This also starts screen in "detached" mode, but doesn't fork
a new process. The command exits if the session terminates.
-O selects an optimal output mode for your terminal rather than
true VT100 emulation (only affects auto-margin terminals without
`LP'). This can also be set in your .screenrc by specifying
`OP' in a "termcap" command.
-p number_or_name|-|=|+
Preselect a window. This is useful when you want to reattach to
a specific window or you want to send a command via the "-X"
option to a specific window. As with screen's select command,
"-" selects the blank window. As a special case for reattach,
"=" brings up the windowlist on the blank window, while a "+"
will create a new window. The command will not be executed if
the specified window could not be found.
-q Suppress printing of error messages. In combination with "-ls"
the exit value is as follows: 9 indicates a directory without
sessions. 10 indicates a directory with running but not
attachable sessions. 11 (or more) indicates 1 (or more) usable
sessions. In combination with "-r" the exit value is as
follows: 10 indicates that there is no session to resume. 12 (or
more) indicates that there are 2 (or more) sessions to resume
and you should specify which one to choose. In all other cases
"-q" has no effect.
-Q Some commands now can be queried from a remote session using
this flag, e.g. "screen -Q windows". The commands will send the
response to the stdout of the querying process. If there was an
error in the command, then the querying process will exit with a
non-zero status.
The commands that can be queried now are:
echoinfolastmsgnumberselecttimetitlewindows-r [pid.tty.host]
-r sessionowner/[pid.tty.host]
resumes a detached screen session. No other options (except
combinations with -d/-D) may be specified, though an optional
prefix of [pid.]tty.host may be needed to distinguish between
multiple detached screen sessions. The second form is used to
connect to another user's screen session which runs in multiuser
mode. This indicates that screen should look for sessions in
another user's directory. This requires setuid-root.
-R resumes screen only when it's unambiguous which one to attach,
usually when only one screen is detached. Otherwise lists
available sessions. -RR attempts to resume the first detached
screen session it finds. If successful, all other command-line
options are ignored. If no detached session exists, starts a
new session using the specified options, just as if -R had not
been specified. The option is set by default if screen is run as
a login-shell (actually screen uses "-xRR" in that case). For
combinations with the -d/-D option see there.
-s program
sets the default shell to the program specified, instead of the
value in the environment variable $SHELL (or "/bin/sh" if not
defined). This can also be defined through the "shell"
.screenrc command. See also there.
-S sessionname
When creating a new session, this option can be used to specify
a meaningful name for the session. This name identifies the
session for "screen -list" and "screen -r" actions. It
substitutes the default [tty.host] suffix.
-t name
sets the title (a.k.a.) for the default shell or specified
program. See also the "shelltitle" .screenrc command.
-T term
Set the $TERM environment variable using the specified term as
opposed to the default setting of screen.
-U Run screen in UTF-8 mode. This option tells screen that your
terminal sends and understands UTF-8 encoded characters. It also
sets the default encoding for new windows to `utf8'.
-v Print version number.
-wipe [match]
does the same as "screen -ls", but removes destroyed sessions
instead of marking them as `dead'. An unreachable session is
considered dead, when its name matches either the name of the
local host, or the explicitly given parameter, if any. See the
-r flag for a description how to construct matches.
-x Attach to a not detached screen session. (Multi display mode).
Screen refuses to attach from within itself. But when cascading
multiple screens, loops are not detected; take care.
-X Send the specified command to a running screen session. You may
use the -S option to specify the screen session if you have
several screen sessions running. You can use the -d or -r option
to tell screen to look only for attached or detached screen
sessions. Note that this command doesn't work if the session is
password protected.
-4 Resolve hostnames only to IPv4 addresses.
-6 Resolve hostnames only to IPv6 addresses.

The "socket directory" defaults either to $HOME/.screen or simply to
/tmp/screens or preferably to /usr/local/screens chosen at compile-
time. If screen is installed setuid-root, then the administrator
should compile screen with an adequate (not NFS mounted) socket
directory. If screen is not running setuid-root, the user can specify
any mode 700 directory in the environment variable $SCREENDIR.
When screen is invoked, it executes initialization commands from the
files "/usr/local/etc/screenrc" and ".screenrc" in the user's home
directory. These are the "programmer's defaults" that can be
overridden in the following ways: for the global screenrc file screen
searches for the environment variable $SYSTEM_SCREENRC (this override
feature may be disabled at compile-time). The user specific screenrc
file is searched in $SCREENRC, then $HOME/.screenrc. The command
line option -c takes precedence over the above user screenrc files.
Commands in these files are used to set options, bind functions to
keys, and to automatically establish one or more windows at the
beginning of your screen session. Commands are listed one per line,
with empty lines being ignored. A command's arguments are separated
by tabs or spaces, and may be surrounded by single or double quotes.
A `#' turns the rest of the line into a comment, except in quotes.
Unintelligible lines are warned about and ignored. Commands may
contain references to environment variables. The syntax is the shell-
like "$VAR " or "${VAR}". Note that this causes incompatibility with
previous screen versions, as now the '$'-character has to be
protected with '\' if no variable substitution shall be performed. A
string in single-quotes is also protected from variable substitution.
Two configuration files are shipped as examples with your screen
distribution: "etc/screenrc" and "etc/etcscreenrc". They contain a
number of useful examples for various commands.
Customization can also be done 'on-line'. To enter the command mode
type `C-a :'. Note that commands starting with "def" change default
values, while others change current settings.
The following commands are available:
acladd usernames [crypted-pw]
addacl usernames
Enable users to fully access this screen session. Usernames can be
one user or a comma separated list of users. This command enables to
attach to the screen session and performs the equivalent of `aclchg
usernames +rwx "#?"'. executed. To add a user with restricted
access, use the `aclchg' command below. If an optional second
parameter is supplied, it should be a crypted password for the named
user(s). `Addacl' is a synonym to `acladd'. Multi user mode only.
aclchg usernames permbits listchacl usernames permbits list
Change permissions for a comma separated list of users. Permission
bits are represented as `r', `w' and `x'. Prefixing `+' grants the
permission, `-' removes it. The third parameter is a comma separated
list of commands and/or windows (specified either by number or
title). The special list `#' refers to all windows, `?' to all
commands. if usernames consists of a single `*', all known users are
affected.
A command can be executed when the user has the `x' bit for it. The
user can type input to a window when he has its `w' bit set and no
other user obtains a writelock for this window. Other bits are
currently ignored. To withdraw the writelock from another user in
window 2: `aclchg username -w+w 2'. To allow read-only access to the
session: `aclchg username -w "#"'. As soon as a user's name is known
to screen he can attach to the session and (per default) has full
permissions for all command and windows. Execution permission for the
acl commands, `at' and others should also be removed or the user may
be able to regain write permission. Rights of the special username
nobody cannot be changed (see the "su" command). `Chacl' is a
synonym to `aclchg'. Multi user mode only.
acldel username
Remove a user from screen's access control list. If currently
attached, all the user's displays are detached from the session. He
cannot attach again. Multi user mode only.
aclgrp username [groupname]
Creates groups of users that share common access rights. The name of
the group is the username of the group leader. Each member of the
group inherits the permissions that are granted to the group leader.
That means, if a user fails an access check, another check is made
for the group leader. A user is removed from all groups the special
value "none" is used for groupname. If the second parameter is
omitted all groups the user is in are listed.
aclumask [[ users ] +bits | [ users ] -bits... ]
umask [[ users ] +bits | [ users ] -bits... ]
This specifies the access other users have to windows that will be
created by the caller of the command. Users may be no, one or a
comma separated list of known usernames. If no users are specified, a
list of all currently known users is assumed. Bits is any
combination of access control bits allowed defined with the "aclchg"
command. The special username "?" predefines the access that not yet
known users will be granted to any window initially. The special
username "??" predefines the access that not yet known users are
granted to any command. Rights of the special username nobody cannot
be changed (see the "su" command). `Umask' is a synonym to
`aclumask'.
activity message
When any activity occurs in a background window that is being
monitored, screen displays a notification in the message line. The
notification message can be re-defined by means of the "activity"
command. Each occurrence of `%' in message is replaced by the number
of the window in which activity has occurred, and each occurrence of
`^G' is replaced by the definition for bell in your termcap (usually
an audible bell). The default message is
'Activity in window %n'
Note that monitoring is off for all windows by default, but can be
altered by use of the "monitor" command (C-a M).
allpartial on|off
If set to on, only the current cursor line is refreshed on window
change. This affects all windows and is useful for slow terminal
lines. The previous setting of full/partial refresh for each window
is restored with "allpartial off". This is a global flag that
immediately takes effect on all windows overriding the "partial"
settings. It does not change the default redraw behavior of newly
created windows.
altscreen on|off
If set to on, "alternate screen" support is enabled in virtual
terminals, just like in xterm. Initial setting is `off'.
at [identifier][#|*|%] command [args... ]
Execute a command at other displays or windows as if it had been
entered there. "At" changes the context (the `current window' or
`current display' setting) of the command. If the first parameter
describes a non-unique context, the command will be executed multiple
times. If the first parameter is of the form `identifier*' then
identifier is matched against user names. The command is executed
once for each display of the selected user(s). If the first parameter
is of the form `identifier%' identifier is matched against displays.
Displays are named after the ttys they attach. The prefix `/dev/' or
`/dev/tty' may be omitted from the identifier. If identifier has a
`#' or nothing appended it is matched against window numbers and
titles. Omitting an identifier in front of the `#', `*' or
`%'-character selects all users, displays or windows because a
prefix-match is performed. Note that on the affected display(s) a
short message will describe what happened. Permission is checked for
initiator of the "at" command, not for the owners of the affected
display(s). Note that the '#' character works as a comment
introducer when it is preceded by whitespace. This can be escaped by
prefixing a '\'. Permission is checked for the initiator of the "at"
command, not for the owners of the affected display(s).
Caveat: When matching against windows, the command is executed at
least once per window. Commands that change the internal arrangement
of windows (like "other") may be called again. In shared windows the
command will be repeated for each attached display. Beware, when
issuing toggle commands like "login"! Some commands (e.g. "process")
require that a display is associated with the target windows. These
commands may not work correctly under "at" looping over windows.
attrcolor attrib [attribute/color-modifier]
This command can be used to highlight attributes by changing the
color of the text. If the attribute attrib is in use, the specified
attribute/color modifier is also applied. If no modifier is given,
the current one is deleted. See the "STRING ESCAPES" chapter for the
syntax of the modifier. Screen understands two pseudo-attributes, "i"
stands for high-intensity foreground color and "I" for high-intensity
background color.
Examples:
attrcolor b "R"
Change the color to bright red if bold text is to be printed.
attrcolor u "-u b"
Use blue text instead of underline.
attrcolor b ".I"
Use bright colors for bold text. Most terminal emulators do this
already.
attrcolor i "+b"
Make bright colored text also bold.
autodetach on|off
Sets whether screen will automatically detach upon hangup, which
saves all your running programs until they are resumed with a screen-r command. When turned off, a hangup signal will terminate screen
and all the processes it contains. Autodetach is on by default.
autonuke on|off
Sets whether a clear screen sequence should nuke all the output that
has not been written to the terminal. See also "obuflimit".
backtick id lifespan autorefresh cmd args...backtick id
Program the backtick command with the numerical id id. The output of
such a command is used for substitution of the "%`" string escape.
The specified lifespan is the number of seconds the output is
considered valid. After this time, the command is run again if a
corresponding string escape is encountered. The autorefresh
parameter triggers an automatic refresh for caption and hardstatus
strings after the specified number of seconds. Only the last line of
output is used for substitution.
If both the lifespan and the autorefresh parameters are zero, the
backtick program is expected to stay in the background and generate
output once in a while. In this case, the command is executed right
away and screen stores the last line of output. If a new line gets
printed screen will automatically refresh the hardstatus or the
captions.
The second form of the command deletes the backtick command with the
numerical id id.
bce [on|off]
Change background-color-erase setting. If "bce" is set to on, all
characters cleared by an erase/insert/scroll/clear operation will be
displayed in the current background color. Otherwise the default
background color is used.
bell_msg [message]
When a bell character is sent to a background window, screen displays
a notification in the message line. The notification message can be
re-defined by this command. Each occurrence of `%' in message is
replaced by the number of the window to which a bell has been sent,
and each occurrence of `^G' is replaced by the definition for bell in
your termcap (usually an audible bell). The default message is
'Bell in window %n'
An empty message can be supplied to the "bell_msg" command to
suppress output of a message line (bell_msg ""). Without parameter,
the current message is shown.
bind [class] key [command [args]]
Bind a command to a key. By default, most of the commands provided
by screen are bound to one or more keys as indicated in the "DEFAULT
KEY BINDINGS" section, e.g. the command to create a new window is
bound to "C-c" and "c". The "bind" command can be used to redefine
the key bindings and to define new bindings. The key argument is
either a single character, a two-character sequence of the form "^x"
(meaning "C-x"), a backslash followed by an octal number (specifying
the ASCII code of the character), or a backslash followed by a second
character, such as "\^" or "\\". The argument can also be quoted, if
you like. If no further argument is given, any previously
established binding for this key is removed. The command argument
can be any command listed in this section.
If a command class is specified via the "-c" option, the key is bound
for the specified class. Use the "command" command to activate a
class. Command classes can be used to create multiple command keys or
multi-character bindings.
Some examples:
bind ' ' windows
bind ^k
bind k
bind K kill
bind ^f screen telnet foobar
bind \033 screen -ln -t root -h 1000 9 su
would bind the space key to the command that displays a list of
windows (so that the command usually invoked by "C-a C-w" would also
be available as "C-a space"). The next three lines remove the default
kill binding from "C-a C-k" and "C-a k". "C-a K" is then bound to
the kill command. Then it binds "C-f" to the command "create a window
with a TELNET connection to foobar", and bind "escape" to the command
that creates an non-login window with a.k.a. "root" in slot #9, with
a superuser shell and a scrollback buffer of 1000 lines.
bind -c demo1 0 select 10
bind -c demo1 1 select 11
bind -c demo1 2 select 12
bindkey "^B" command -c demo1
makes "C-b 0" select window 10, "C-b 1" window 11, etc.
bind -c demo2 0 select 10
bind -c demo2 1 select 11
bind -c demo2 2 select 12
bind - command -c demo2
makes "C-a - 0" select window 10, "C-a - 1" window 11, etc.
bindkey [-d] [-m] [-a] [[-k|-t] string [cmd-args]]
This command manages screen's input translation tables. Every entry
in one of the tables tells screen how to react if a certain sequence
of characters is encountered. There are three tables: one that should
contain actions programmed by the user, one for the default actions
used for terminal emulation and one for screen's copy mode to do
cursor movement. See section "INPUT TRANSLATION" for a list of
default key bindings.
If the -d option is given, bindkey modifies the default table, -m
changes the copy mode table and with neither option the user table is
selected. The argument string is the sequence of characters to which
an action is bound. This can either be a fixed string or a termcap
keyboard capability name (selectable with the -k option).
Some keys on a VT100 terminal can send a different string if
application mode is turned on (e.g the cursor keys). Such keys have
two entries in the translation table. You can select the application
mode entry by specifying the -a option.
The -t option tells screen not to do inter-character timing. One
cannot turn off the timing if a termcap capability is used.
Cmd can be any of screen's commands with an arbitrary number of args.
If cmd is omitted the key-binding is removed from the table.
Here are some examples of keyboard bindings:
bindkey -d
Show all of the default key bindings. The application mode entries
are marked with [A].
bindkey -k k1 select 1
Make the "F1" key switch to window one.
bindkey -t foo stuff barfoo
Make "foo" an abbreviation of the word "barfoo". Timeout is disabled
so that users can type slowly.
bindkey "\024" mapdefault
This key-binding makes "^T" an escape character for key-bindings. If
you did the above "stuff barfoo" binding, you can enter the word
"foo" by typing "^Tfoo". If you want to insert a "^T" you have to
press the key twice (i.e., escape the escape binding).
bindkey -k F1 command
Make the F11 (not F1!) key an alternative screen escape (besides ^A).
break[duration]
Send a break signal for duration*0.25 seconds to this window. For
non-Posix systems the time interval may be rounded up to full
seconds. Most useful if a character device is attached to the window
rather than a shell process (See also chapter "WINDOW TYPES"). The
maximum duration of a break signal is limited to 15 seconds.
blanker
Activate the screen blanker. First the screen is cleared. If no
blanker program is defined, the cursor is turned off, otherwise, the
program is started and it's output is written to the screen. The
screen blanker is killed with the first keypress, the read key is
discarded.
This command is normally used together with the "idle" command.
blankerprg [program-args]
Defines a blanker program. Disables the blanker program if an empty
argument is given. Shows the currently set blanker program if no
arguments are given.
breaktype [tcsendbreak|TIOCSBRK|TCSBRK]
Choose one of the available methods of generating a break signal for
terminal devices. This command should affect the current window only.
But it still behaves identical to "defbreaktype". This will be
changed in the future. Calling "breaktype" with no parameter
displays the break method for the current window.
bufferfile [exchange-file]
Change the filename used for reading and writing with the paste
buffer. If the optional argument to the "bufferfile" command is
omitted, the default setting ("/tmp/screen-exchange") is reactivated.
The following example will paste the system's password file into the
screen window (using the paste buffer, where a copy remains):
C-a : bufferfile /etc/passwd
C-a < C-a ]
C-a : bufferfile
bumpleft
Swaps window with previous one on window list.
bumpright
Swaps window with next one on window list.
c1 [on|off]
Change c1 code processing. "C1 on" tells screen to treat the input
characters between 128 and 159 as control functions. Such an 8-bit
code is normally the same as ESC followed by the corresponding 7-bit
code. The default setting is to process c1 codes and can be changed
with the "defc1" command. Users with fonts that have usable
characters in the c1 positions may want to turn this off.
caption [ top | bottom ] always|splitonly[string]
caption string [string]
This command controls the display of the window captions. Normally a
caption is only used if more than one window is shown on the display
(split screen mode). But if the type is set to always screen shows a
caption even if only one window is displayed. The default is
splitonly.
The second form changes the text used for the caption. You can use
all escapes from the "STRING ESCAPES" chapter. Screen uses a default
of `%3n %t'.
You can mix both forms by providing a string as an additional
argument.
You can have the caption displayed either at the top or bottom of the
window. The default is bottom.
charset set
Change the current character set slot designation and charset
mapping. The first four character of set are treated as charset
designators while the fifth and sixth character must be in range '0'
to '3' and set the GL/GR charset mapping. On every position a '.' may
be used to indicate that the corresponding charset/mapping should not
be changed (set is padded to six characters internally by appending
'.' chars). New windows have "BBBB02" as default charset, unless a
"encoding" command is active.
The current setting can be viewed with the "info" command.
chdir [directory]
Change the current directory of screen to the specified directory or,
if called without an argument, to your home directory (the value of
the environment variable $HOME). All windows that are created by
means of the "screen" command from within ".screenrc" or by means of
"C-a : screen ..." or "C-a c" use this as their default directory.
Without a chdir command, this would be the directory from which
screen was invoked.
Hardcopy and log files are always written to the window's default
directory, not the current directory of the process running in the
window. You can use this command multiple times in your .screenrc to
start various windows in different default directories, but the last
chdir value will affect all the windows you create interactively.
cjkwidth [ on | off ]
Treat ambiguous width characters as full/half width.
clear
Clears the current window and saves its image to the scrollback
buffer.
collapse
Reorders window on window list, removing number gaps between them.
colon [prefix]
Allows you to enter ".screenrc" command lines. Useful for on-the-fly
modification of key bindings, specific window creation and changing
settings. Note that the "set" keyword no longer exists! Usually
commands affect the current window rather than default settings for
future windows. Change defaults with commands starting with 'def...'.
If you consider this as the `Ex command mode' of screen, you may
regard "C-a esc" (copy mode) as its `Vi command mode'.
command [-c class]
This command has the same effect as typing the screen escape
character (^A). It is probably only useful for key bindings. If the
"-c" option is given, select the specified command class. See also
"bind" and "bindkey".
compacthist [on|off]
This tells screen whether to suppress trailing blank lines when
scrolling up text into the history buffer.
console [on|off]
Grabs or un-grabs the machines console output to a window. Note:
Only the owner of /dev/console can grab the console output. This
command is only available if the machine supports the ioctl TIOCCONS.
copy
Enter copy/scrollback mode. This allows you to copy text from the
current window and its history into the paste buffer. In this mode a
vi-like `full screen editor' is active:
The editor's movement keys are:
────────────────────────────────────────────────────────────────
h, C-h, move the cursor left.
left arrow
────────────────────────────────────────────────────────────────
j, C-n, move the cursor down.
down arrow
────────────────────────────────────────────────────────────────
k, C-p, move the cursor up.
up arrow
────────────────────────────────────────────────────────────────
l ('el'), move the cursor right.
right arrow
────────────────────────────────────────────────────────────────
0 (zero) C-a move to the leftmost column.
────────────────────────────────────────────────────────────────
+ and - positions one line up and down.
────────────────────────────────────────────────────────────────
H, M and L move the cursor to the leftmost column of the
top, center or bottom line of the window.
────────────────────────────────────────────────────────────────
| moves to the specified absolute column.
────────────────────────────────────────────────────────────────
g or home moves to the beginning of the buffer.
────────────────────────────────────────────────────────────────
G or end moves to the specified absolute line (default:
end of buffer).
────────────────────────────────────────────────────────────────
% jumps to the specified percentage of the buffer.
────────────────────────────────────────────────────────────────
^ or $ move to the leftmost column, to the first or
last non-whitespace character on the line.
────────────────────────────────────────────────────────────────
w, b, and e move the cursor word by word.
────────────────────────────────────────────────────────────────
B, E move the cursor WORD by WORD (as in vi).
────────────────────────────────────────────────────────────────
f/F, t/T move the cursor forward/backward to the next
occurence of the target. (eg, '3fy' will move
the cursor to the 3rd 'y' to the right.)
────────────────────────────────────────────────────────────────
; and , Repeat the last f/F/t/T command in the
same/opposite direction.
────────────────────────────────────────────────────────────────
C-e and C-y scroll the display up/down by one line while
preserving the cursor position.
────────────────────────────────────────────────────────────────
C-u and C-d scroll the display up/down by the specified
amount of lines while preserving the cursor
position. (Default: half screen-full).
────────────────────────────────────────────────────────────────
C-b and C-f scroll the display up/down a full screen.
────────────────────────────────────────────────────────────────
Note: Emacs style movement keys can be customized by a .screenrc
command. (E.g. markkeys "h=^B:l=^F:$=^E") There is no simple method
for a full emacs-style keymap, as this involves multi-character
codes.
Some keys are defined to do mark and replace operations.
The copy range is specified by setting two marks. The text between
these marks will be highlighted. Press:
space or enter to set the first or second mark respectively.
If mousetrack is set to `on', marks can also be set using leftmouse click.
Y and y used to mark one whole line or to mark from start of
line.
W marks exactly one word.
Any of these commands can be prefixed with a repeat count number by
pressing digits
0..9 which is taken as a repeat count.
Example: "C-a C-[ H 10 j 5 Y" will copy lines 11 to 15 into the paste
buffer.
The folllowing search keys are defined:
/ Vi-like search forward.
? Vi-like search backward.
C-a s Emacs style incremental search forward.
C-r Emacs style reverse i-search.
n Find next search pattern.
N Find previous search pattern.
There are however some keys that act differently than in vi. Vi does
not allow one to yank rectangular blocks of text, but screen does.
Press: c or C to set the left or right margin respectively. If no
repeat count is given, both default to the current cursor position.
Example: Try this on a rather full text screen:
"C-a [ M 20 l SPACE c 10 l 5 j C SPACE".
This moves one to the middle line of the screen, moves in 20 columns
left, marks the beginning of the paste buffer, sets the left column,
moves 5 columns down, sets the right column, and then marks the end
of the paste buffer. Now try:
"C-a [ M 20 l SPACE 10 l 5 j SPACE"
and notice the difference in the amount of text copied.
J joins lines. It toggles between 4 modes: lines separated by a
newline character (012), lines glued seamless, lines separated by a
single whitespace and comma separated lines. Note that you can
prepend the newline character with a carriage return character, by
issuing a "crlf on".
v or V is for all the vi users with ":set numbers" - it toggles the
left margin between column 9 and 1. Press
a before the final space key to toggle in append mode. Thus the
contents of the paste buffer will not be overwritten, but is appended
to.
A toggles in append mode and sets a (second) mark.
> sets the (second) mark and writes the contents of the paste buffer
to the screen-exchange file (/tmp/screen-exchange per default) once
copy-mode is finished.
This example demonstrates how to dump the whole scrollback buffer to
that file: "C-A [ g SPACE G $ >".
C-g gives information about the current line and column.
x or o exchanges the first mark and the current cursor position. You
can use this to adjust an already placed mark.
C-l ('el') will redraw the screen.
@ does nothing. Does not even exit copy mode.
All keys not described here exit copy mode.
copy_reg [key]
No longer exists, use "readreg" instead.
crlf [on|off]
This affects the copying of text regions with the `C-a [' command. If
it is set to `on', lines will be separated by the two character
sequence `CR' - `LF'. Otherwise (default) only `LF' is used. When
no parameter is given, the state is toggled.
defc1 on|off
Same as the c1 command except that the default setting for new
windows is changed. Initial setting is `on'.
defautonuke on|off
Same as the autonuke command except that the default setting for new
displays is changed. Initial setting is `off'. Note that you can use
the special `AN' terminal capability if you want to have a dependency
on the terminal type.
defbce on|off
Same as the bce command except that the default setting for new
windows is changed. Initial setting is `off'.
defbreaktype [tcsendbreak|TIOCSBRK|TCSBRK]
Choose one of the available methods of generating a break signal for
terminal devices. The preferred methods are tcsendbreak and TIOCSBRK.
The third, TCSBRK, blocks the complete screen session for the
duration of the break, but it may be the only way to generate long
breaks. Tcsendbreak and TIOCSBRK may or may not produce long breaks
with spikes (e.g. 4 per second). This is not only system-dependent,
this also differs between serial board drivers. Calling
"defbreaktype" with no parameter displays the current setting.
defcharset [set]
Like the charset command except that the default setting for new
windows is changed. Shows current default if called without argument.
defdynamictitle on|off
Set default behaviour for new windows regarding if screen should
change window title when seeing proper escape sequence. See also
"TITLES (naming windows)" section.
defescape xy
Set the default command characters. This is equivalent to the
"escape" except that it is useful multiuser sessions only. In a
multiuser session "escape" changes the command character of the
calling user, where "defescape" changes the default command
characters for users that will be added later.
defflow on|off|auto [interrupt]
Same as the flow command except that the default setting for new
windows is changed. Initial setting is `auto'. Specifying "defflow
auto interrupt" is the same as the command-line options -fa and -i.
defgr on|off
Same as the gr command except that the default setting for new
windows is changed. Initial setting is `off'.
defhstatus [status]
The hardstatus line that all new windows will get is set to status.
This command is useful to make the hardstatus of every window display
the window number or title or the like. Status may contain the same
directives as in the window messages, but the directive escape
character is '^E' (octal 005) instead of '%'. This was done to make
a misinterpretation of program generated hardstatus lines impossible.
If the parameter status is omitted, the current default string is
displayed. Per default the hardstatus line of new windows is empty.
defencoding enc
Same as the encoding command except that the default setting for new
windows is changed. Initial setting is the encoding taken from the
terminal.
deflog on|off
Same as the log command except that the default setting for new
windows is changed. Initial setting is `off'.
deflogin on|off
Same as the login command except that the default setting for new
windows is changed. This is initialized with `on' as distributed (see
config.h.in).
defmode mode
The mode of each newly allocated pseudo-tty is set to mode. Mode is
an octal number. When no "defmode" command is given, mode 0622 is
used.
defmonitor on|off
Same as the monitor command except that the default setting for new
windows is changed. Initial setting is `off'.
defmousetrack on|off
Same as the mousetrack command except that the default setting for
new windows is changed. Initial setting is `off'.
defnonblock on|off|numsecs
Same as the nonblock command except that the default setting for
displays is changed. Initial setting is `off'.
defobuflimit limit
Same as the obuflimit command except that the default setting for new
displays is changed. Initial setting is 256 bytes. Note that you can
use the special 'OL' terminal capability if you want to have a
dependency on the terminal type.
defscrollback num
Same as the scrollback command except that the default setting for
new windows is changed. Initial setting is 100.
defshell command
Synonym to the shell .screenrc command. See there.
defsilence on|off
Same as the silence command except that the default setting for new
windows is changed. Initial setting is `off'.
defslowpaste msec
Same as the slowpaste command except that the default setting for new
windows is changed. Initial setting is 0 milliseconds, meaning `off'.
defutf8 on|off
Same as the utf8 command except that the default setting for new
windows is changed. Initial setting is `on' if screen was started
with "-U", otherwise `off'.
defwrap on|off
Same as the wrap command except that the default setting for new
windows is changed. Initially line-wrap is on and can be toggled with
the "wrap" command ("C-a r") or by means of "C-a : wrap on|off".
defwritelock on|off|auto
Same as the writelock command except that the default setting for new
windows is changed. Initially writelocks will off.
detach [-h]
Detach the screen session (disconnect it from the terminal and put it
into the background). This returns you to the shell where you
invoked screen. A detached screen can be resumed by invoking screen
with the -r option (see also section "COMMAND-LINE OPTIONS"). The -h
option tells screen to immediately close the connection to the
terminal ("hangup").
dinfo
Show what screen thinks about your terminal. Useful if you want to
know why features like color or the alternate charset don't work.
displays
Shows a tabular listing of all currently connected user front-ends
(displays). This is most useful for multiuser sessions. The
following keys can be used in displays list:
───────────────────────────────────────────────────────
k, C-p, or up Move up one line.
───────────────────────────────────────────────────────
j, C-n, or down Move down one line.
───────────────────────────────────────────────────────
C-a or home Move to the first line.
───────────────────────────────────────────────────────
C-e or end Move to the last line.
───────────────────────────────────────────────────────
C-u or C-d Move one half page up or down.
───────────────────────────────────────────────────────
C-b or C-f Move one full page up or down.
───────────────────────────────────────────────────────
mouseclick Move to the selected line.
Available when "mousetrack" is
set to on.
───────────────────────────────────────────────────────
space Refresh the list
───────────────────────────────────────────────────────
d Detach that display
───────────────────────────────────────────────────────
D Power detach that display
───────────────────────────────────────────────────────
C-g, enter, or escape Exit the list
───────────────────────────────────────────────────────
The following is an example of what "displays" could look like:
xterm 80x42 jnweiger@/dev/ttyp4 0(m11) &rWx
facit 80x24 mlschroe@/dev/ttyhf nb 11(tcsh) rwx
xterm 80x42 jnhollma@/dev/ttyp5 0(m11) &R.x
(A) (B) (C) (D) (E) (F)(G) (H)(I)
The legend is as follows:
(A) The terminal type known by screen for this display.
(B) Displays geometry as width x height.
(C) Username who is logged in at the display.
(D) Device name of the display or the attached device
(E) Display is in blocking or nonblocking mode. The available
modes are "nb", "NB", "Z<", "Z>", and "BL".
(F) Number of the window
(G) Name/title of window
(H) Whether the window is shared
(I) Window permissions. Made up of three characters.
┌────────────────────────────────────────────────────────┐
│ Window permissions indicators │
├─────────────────┬──────────────────┬───────────────────┤
│ 1st character │ 2nd character │ 3rd character │
├────┬────────────┼─────┬────────────┼─────┬─────────────┤
│- │no read │ - │no write │ - │no execute │
├────┼────────────┼─────┼────────────┼─────┼─────────────┤
│r │read │ w │write │ x │execute │
├────┼────────────┼─────┼────────────┼─────┼─────────────┤
│ │ │ W │own wlock │ │ │
├────┴────────────┴─────┴────────────┴─────┴─────────────┤
│Indicators of permissions suppressed by a foreign wlock │
├────┬────────────┬─────┬────────────┬─────┬─────────────┤
│R │read only │ . │no write │ │ │
└────┴────────────┴─────┴────────────┴─────┴─────────────┘
"displays" needs a region size of at least 10 characters wide
and 5 characters high in order to display.
digraph [preset[unicode-value]]
This command prompts the user for a digraph sequence. The next two
characters typed are looked up in a builtin table and the resulting
character is inserted in the input stream. For example, if the user
enters 'a"', an a-umlaut will be inserted. If the first character
entered is a 0 (zero), screen will treat the following characters (up
to three) as an octal number instead. The optional argument preset
is treated as user input, thus one can create an "umlaut" key. For
example the command "bindkey ^K digraph '"'" enables the user to
generate an a-umlaut by typing CTRL-K a. When a non-zero unicode-value is specified, a new digraph is created with the specified
preset. The digraph is unset if a zero value is provided for the
unicode-value.dumptermcap
Write the termcap entry for the virtual terminal optimized for the
currently active window to the file ".termcap" in the user's
"$HOME/.screen" directory (or wherever screen stores its sockets. See
the "FILES" section below). This termcap entry is identical to the
value of the environment variable $TERMCAP that is set up by screen
for each window. For terminfo based systems you will need to run a
converter like captoinfo and then compile the entry with tic.
dynamictitle on|off
Change behaviour for windows regarding if screen should change window
title when seeing proper escape sequence. See also "TITLES (naming
windows)" section.
echo [-n] message
The echo command may be used to annoy screen users with a 'message of
the day'. Typically installed in a global /local/etc/screenrc. The
option "-n" may be used to suppress the line feed. See also "sleep".
Echo is also useful for online checking of environment variables.
encoding enc [enc]
Tell screen how to interpret the input/output. The first argument
sets the encoding of the current window. Each window can emulate a
different encoding. The optional second parameter overwrites the
encoding of the connected terminal. It should never be needed as
screen uses the locale setting to detect the encoding. There is also
a way to select a terminal encoding depending on the terminal type by
using the "KJ" termcap entry.
Supported encodings are eucJP, SJIS, eucKR, eucCN, Big5, GBK, KOI8-R,
KOI8-U, CP1251, UTF-8, ISO8859-2, ISO8859-3, ISO8859-4, ISO8859-5,
ISO8859-6, ISO8859-7, ISO8859-8, ISO8859-9, ISO8859-10, ISO8859-15,
jis.
See also "defencoding", which changes the default setting of a new
window.
escape xy
Set the command character to x and the character generating a literal
command character (by triggering the "meta" command) to y (similar to
the -e option). Each argument is either a single character, a two-
character sequence of the form "^x" (meaning "C-x"), a backslash
followed by an octal number (specifying the ASCII code of the
character), or a backslash followed by a second character, such as
"\^" or "\\". The default is "^Aa".
eval command1[command2 ...]
Parses and executes each argument as separate command.
exec [[fdpat]newcommand [args ...]]
Run a unix subprocess (specified by an executable path newcommand and
its optional arguments) in the current window. The flow of data
between newcommands stdin/stdout/stderr, the process originally
started in the window (let us call it "application-process") and
screen itself (window) is controlled by the file descriptor pattern
fdpat. This pattern is basically a three character sequence
representing stdin, stdout and stderr of newcommand. A dot (.)
connects the file descriptor to screen. An exclamation mark (!)
causes the file descriptor to be connected to the application-
process. A colon (:) combines both. User input will go to newcommand
unless newcommand receives the application-process' output (fdpats
first character is `!' or `:') or a pipe symbol (|) is added (as a
fourth character) to the end of fdpat.
Invoking `exec' without arguments shows name and arguments of the
currently running subprocess in this window. Only one subprocess a
time can be running in each window.
When a subprocess is running the `kill' command will affect it
instead of the windows process.
Refer to the postscript file `doc/fdpat.ps' for a confusing
illustration of all 21 possible combinations. Each drawing shows the
digits 2,1,0 representing the three file descriptors of newcommand.
The box marked `W' is the usual pty that has the application-process
on its slave side. The box marked `P' is the secondary pty that now
has screen at its master side.
Abbreviations: Whitespace between the word `exec' and fdpat and the
command can be omitted. Trailing dots and a fdpat consisting only of
dots can be omitted. A simple `|' is synonymous for the pattern
`!..|'; the word exec can be omitted here and can always be replaced
by `!'.
Examples:
exec ... /bin/sh
exec /bin/sh
!/bin/sh
Creates another shell in the same window, while the
original shell is still running. Output of both shells
is displayed and user input is sent to the new /bin/sh.
exec !.. stty 19200
exec ! stty 19200
!!stty 19200
Set the speed of the window's tty. If your stty command
operates on stdout, then add another `!'.
exec !..| less
|less
This adds a pager to the window output. The special
character `|' is needed to give the user control over
the pager although it gets its input from the window's
process. This works, because less listens on stderr (a
behavior that screen would not expect without the `|')
when its stdin is not a tty. Less versions newer than
177 fail miserably here; good old pg still works.
!:sed -n s/.*Error.*/\007/p
Sends window output to both, the user and the sed
command. The sed inserts an additional bell character
(oct. 007) to the window output seen by screen. This
will cause "Bell in window x" messages, whenever the
string "Error" appears in the window.
fit
Change the window size to the size of the current region. This
command is needed because screen doesn't adapt the window size
automatically if the window is displayed more than once.
flow [on|off|auto]
Sets the flow-control mode for this window. Without parameters it
cycles the current window's flow-control setting from "automatic" to
"on" to "off". See the discussion on "FLOW-CONTROL" later on in this
document for full details and note, that this is subject to change in
future releases. Default is set by `defflow'.
focus [next|prev|up|down|left|right|top|bottom]
Move the input focus to the next region. This is done in a cyclic way
so that the top left region is selected after the bottom right one.
If no option is given it defaults to `next'. The next region to be
selected is determined by how the regions are layered. Normally, the
next region in the same layer would be selected. However, if that
next region contains one or more layers, the first region in the
highest layer is selected first. If you are at the last region of the
current layer, `next' will move the focus to the next region in the
lower layer (if there is a lower layer). `Prev' cycles in the
opposite order. See "split" for more information about layers.
The rest of the options (`up', `down', `left', `right', `top', and
`bottom') are more indifferent to layers. The option `up' will move
the focus upward to the region that is touching the upper left corner
of the current region. `Down' will move downward to the region that
is touching the lower left corner of the current region. The option
`left' will move the focus leftward to the region that is touching
the upper left corner of the current region, while `right' will move
rightward to the region that is touching the upper right corner of
the current region. Moving left from a left most region or moving
right from a right most region will result in no action.
The option `top' will move the focus to the very first region in the
upper list corner of the screen, and `bottom' will move to the region
in the bottom right corner of the screen. Moving up from a top most
region or moving down from a bottom most region will result in no
action.
Useful bindings are (h, j, k, and l as in vi)
bind h focus left
bind j focus down
bind k focus up
bind l focus right
bind t focus top
bind b focus bottom
Note that k is traditionally bound to the kill command.
focusminsize [ ( width|max|_ ) ( height|max|_ ) ]
This forces any currently selected region to be automatically resized
at least a certain width and height. All other surrounding regions
will be resized in order to accommodate. This constraint follows
everytime the "focus" command is used. The "resize" command can be
used to increase either dimension of a region, but never below what
is set with "focusminsize". The underscore `_' is a synonym for max.
Setting a width and height of `0 0' (zero zero) will undo any
constraints and allow for manual resizing. Without any parameters,
the minimum width and height is shown.
gr [on|off]
Turn GR charset switching on/off. Whenever screen sees an input
character with the 8th bit set, it will use the charset stored in the
GR slot and print the character with the 8th bit stripped. The
default (see also "defgr") is not to process GR switching because
otherwise the ISO88591 charset would not work.
group [grouptitle]
Change or show the group the current window belongs to. Windows can
be moved around between different groups by specifying the name of
the destination group. Without specifying a group, the title of the
current group is displayed.
hardcopy [-h] [file]
Writes out the currently displayed image to the file file, or, if no
filename is specified, to hardcopy.n in the default directory, where
n is the number of the current window. This either appends or
overwrites the file if it exists. See below. If the option -h is
specified, dump also the contents of the scrollback buffer.
hardcopy_append on|off
If set to "on", screen will append to the "hardcopy.n" files created
by the command "C-a h", otherwise these files are overwritten each
time. Default is `off'.
hardcopydir directory
Defines a directory where hardcopy files will be placed. If unset,
hardcopys are dumped in screen's current working directory.
hardstatus [on|off]
hardstatus [always]firstline|lastline|message|ignore[string]
hardstatus string[string]
This command configures the use and emulation of the terminal's
hardstatus line. The first form toggles whether screen will use the
hardware status line to display messages. If the flag is set to
`off', these messages are overlaid in reverse video mode at the
display line. The default setting is `on'.
The second form tells screen what to do if the terminal doesn't have
a hardstatus line (i.e. the termcap/terminfo capabilities "hs", "ts",
"fs" and "ds" are not set). When "firstline/lastline" is used,
screen will reserve the first/last line of the display for the
hardstatus. "message" uses screen's message mechanism and "ignore"
tells screen never to display the hardstatus. If you prepend the
word "always" to the type (e.g., "alwayslastline"), screen will use
the type even if the terminal supports a hardstatus.
The third form specifies the contents of the hardstatus line. '%h'
is used as default string, i.e., the stored hardstatus of the current
window (settable via "ESC]0;<string>^G" or "ESC_<string>ESC\") is
displayed. You can customize this to any string you like including
the escapes from the "STRING ESCAPES" chapter. If you leave out the
argument string, the current string is displayed.
You can mix the second and third form by providing the string as
additional argument.
height [-w|-d] [lines [cols]]
Set the display height to a specified number of lines. When no
argument is given it toggles between 24 and 42 lines display. You can
also specify a width if you want to change both values. The -w
option tells screen to leave the display size unchanged and just set
the window size, -d vice versa.
help[class]
Not really a online help, but displays a help screen showing you all
the key bindings. The first pages list all the internal commands
followed by their current bindings. Subsequent pages will display
the custom commands, one command per key. Press space when you're
done reading each page, or return to exit early. All other
characters are ignored. If the "-c" option is given, display all
bound commands for the specified command class. See also "DEFAULT
KEY BINDINGS" section.
history
Usually users work with a shell that allows easy access to previous
commands. For example csh has the command "!!" to repeat the last
command executed. Screen allows you to have a primitive way of re-
calling "the command that started ...": You just type the first
letter of that command, then hit `C-a {' and screen tries to find a
previous line that matches with the `prompt character' to the left of
the cursor. This line is pasted into this window's input queue. Thus
you have a crude command history (made up by the visible window and
its scrollback buffer).
hstatus status
Change the window's hardstatus line to the string status.
idle [timeout[cmd-args]]
Sets a command that is run after the specified number of seconds
inactivity is reached. This command will normally be the "blanker"
command to create a screen blanker, but it can be any screen command.
If no command is specified, only the timeout is set. A timeout of
zero (or the special timeout off) disables the timer. If no
arguments are given, the current settings are displayed.
ignorecase [on|off]
Tell screen to ignore the case of characters in searches. Default is
`off'. Without any options, the state of ignorecase is toggled.
info
Uses the message line to display some information about the current
window: the cursor position in the form "(column,row)" starting with
"(1,1)", the terminal width and height plus the size of the
scrollback buffer in lines, like in "(80,24)+50", the current state
of window XON/XOFF flow control is shown like this (See also section
FLOW CONTROL):
┌─────────┬──────────────────────────────────────────────────────────┐
│+flow │ automatic flow control, currently on. │
├─────────┼──────────────────────────────────────────────────────────┤
│-flow │ automatic flow control, currently off. │
├─────────┼──────────────────────────────────────────────────────────┤
│+(+)flow │ flow control enabled. Agrees with automatic control. │
├─────────┼──────────────────────────────────────────────────────────┤
│-(+)flow │ flow control disabled. Disagrees with automatic control. │
├─────────┼──────────────────────────────────────────────────────────┤
│+(-)flow │ flow control enabled. Disagrees with automatic control. │
├─────────┼──────────────────────────────────────────────────────────┤
│-(-)flow │ flow control disabled. Agrees with automatic control. │
└─────────┴──────────────────────────────────────────────────────────┘
The current line wrap setting (`+wrap' indicates enabled, `-wrap'
not) is also shown. The flags `ins', `org', `app', `log', `mon' or
`nored' are displayed when the window is in insert mode, origin mode,
application-keypad mode, has output logging, activity monitoring or
partial redraw enabled.
The currently active character set (G0, G1, G2, or G3) and in square
brackets the terminal character sets that are currently designated as
G0 through G3 is shown. If the window is in UTF-8 mode, the string
"UTF-8" is shown instead.
Additional modes depending on the type of the window are displayed at
the end of the status line (See also chapter "WINDOW TYPES").
If the state machine of the terminal emulator is in a non-default
state, the info line is started with a string identifying the current
state.
For system information use the "time" command.
ins_reg [key]
No longer exists, use "paste" instead.
kill
Kill current window.
If there is an `exec' command running then it is killed. Otherwise
the process (shell) running in the window receives a HANGUP
condition, the window structure is removed and screen (your display)
switches to another window. When the last window is destroyed,
screen exits. After a kill screen switches to the previously
displayed window.
Note: Emacs users should keep this command in mind, when killing a
line. It is recommended not to use "C-a" as the screen escape key or
to rebind kill to "C-a K".
lastmsg
Redisplay the last contents of the message/status line. Useful if
you're typing when a message appears, because the message goes away
when you press a key (unless your terminal has a hardware status
line). Refer to the commands "msgwait" and "msgminwait" for fine
tuning.
layout new [title]
Create a new layout. The screen will change to one whole region and
be switched to the blank window. From here, you build the regions and
the windows they show as you desire. The new layout will be numbered
with the smallest available integer, starting with zero. You can
optionally give a title to your new layout. Otherwise, it will have
a default title of "layout". You can always change the title later by
using the command layout title.
layout remove [n|title]
Remove, or in other words, delete the specified layout. Either the
number or the title can be specified. Without either specification,
screen will remove the current layout.
Removing a layout does not affect your set windows or regions.
layout next
Switch to the next layout available
layout prev
Switch to the previous layout available
layout select [n|title]
Select the desired layout. Either the number or the title can be
specified. Without either specification, screen will prompt and ask
which screen is desired. To see which layouts are available, use the
layout show command.
layout show
List on the message line the number(s) and title(s) of the available
layout(s). The current layout is flagged.
layout title [title]
Change or display the title of the current layout. A string given
will be used to name the layout. Without any options, the current
title and number is displayed on the message line.
layout number [n]
Change or display the number of the current layout. An integer given
will be used to number the layout. Without any options, the current
number and title is displayed on the message line.
layout attach [title|:last]
Change or display which layout to reattach back to. The default is
:last, which tells screen to reattach back to the last used layout
just before detachment. By supplying a title, You can instruct screen
to reattach to a particular layout regardless which one was used at
the time of detachment. Without any options, the layout to reattach
to will be shown in the message line.
layout save [n|title]
Remember the current arrangement of regions. When used, screen will
remember the arrangement of vertically and horizontally split
regions. This arrangement is restored when a screen session is
reattached or switched back from a different layout. If the session
ends or the screen process dies, the layout arrangements are lost.
The layout dump command should help in this siutation. If a number or
title is supplied, screen will remember the arrangement of that
particular layout. Without any options, screen will remember the
current layout.
Saving your regions can be done automatically by using the layoutautosave command.
layout autosave [on|off]
Change or display the status of automatcally saving layouts. The
default is on, meaning when screen is detached or changed to a
different layout, the arrangement of regions and windows will be
remembered at the time of change and restored upon return. If
autosave is set to off, that arrangement will only be restored to
either to the last manual save, using layout save, or to when the
layout was first created, to a single region with a single window.
Without either an on or off, the current status is displayed on the
message line.
layout dump [filename]
Write to a file the order of splits made in the current layout. This
is useful to recreate the order of your regions used in your current
layout. Only the current layout is recorded. While the order of the
regions are recorded, the sizes of those regions and which windows
correspond to which regions are not. If no filename is specified, the
default is layout-dump, saved in the directory that the screen
process was started in. If the file already exists, layout dump will
append to that file. As an example:
C-a : layout dump /home/user/.screenrc
will save or append the layout to the user's .screenrc file.
license
Display the disclaimer page. This is done whenever screen is started
without options, which should be often enough. See also the
"startup_message" command.
lockscreen
Lock this display. Call a screenlock program (/local/bin/lck or
/usr/bin/lock or a builtin if no other is available). Screen does not
accept any command keys until this program terminates. Meanwhile
processes in the windows may continue, as the windows are in the
`detached' state. The screenlock program may be changed through the
environment variable $LOCKPRG (which must be set in the shell from
which screen is started) and is executed with the user's uid and gid.
Warning: When you leave other shells unlocked and you have no
password set on screen, the lock is void: One could easily re-attach
from an unlocked shell. This feature should rather be called
`lockterminal'.
log [on|off]
Start/stop writing output of the current window to a file
"screenlog.n" in the window's default directory, where n is the
number of the current window. This filename can be changed with the
`logfile' command. If no parameter is given, the state of logging is
toggled. The session log is appended to the previous contents of the
file if it already exists. The current contents and the contents of
the scrollback history are not included in the session log. Default
is `off'.
logfile filenamelogfile flush secs
Defines the name the log files will get. The default is
"screenlog.%n". The second form changes the number of seconds screen
will wait before flushing the logfile buffer to the file-system. The
default value is 10 seconds.
login [on|off]
Adds or removes the entry in the utmp database file for the current
window. This controls if the window is `logged in'. When no
parameter is given, the login state of the window is toggled.
Additionally to that toggle, it is convenient having a `log in' and a
`log out' key. E.g. `bind I login on' and `bind O login off' will map
these keys to be C-a I and C-a O. The default setting (in
config.h.in) should be "on" for a screen that runs under suid-root.
Use the "deflogin" command to change the default login state for new
windows. Both commands are only present when screen has been compiled
with utmp support.
logtstamp [on|off]
logtstamp after [secs]
logtstamp string
[string]
This command controls logfile time-stamp mechanism of screen. If
time-stamps are turned "on", screen adds a string containing the
current time to the logfile after two minutes of inactivity. When
output continues and more than another two minutes have passed, a
second time-stamp is added to document the restart of the output. You
can change this timeout with the second form of the command. The
third form is used for customizing the time-stamp string (`-- %n:%t
-- time-stamp -- %M/%d/%y %c:%s --\n' by default).
mapdefault
Tell screen that the next input character should only be looked up in
the default bindkey table. See also "bindkey".
mapnotnext
Like mapdefault, but don't even look in the default bindkey table.
maptimeout [timeout]
Set the inter-character timer for input sequence detection to a
timeout of timeout ms. The default timeout is 300ms. Maptimeout with
no arguments shows the current setting. See also "bindkey".
markkeys string
This is a method of changing the keymap used for copy/history mode.
The string is made up of oldchar=newchar pairs which are separated by
`:'. Example: The string "B=^B:F=^F" will change the keys `C-b' and
`C-f' to the vi style binding (scroll up/down fill page). This
happens to be the default binding for `B' and `F'. The command
"markkeys h=^B:l=^F:$=^E" would set the mode for an emacs-style
binding. If your terminal sends characters, that cause you to abort
copy mode, then this command may help by binding these characters to
do nothing. The no-op character is `@' and is used like this:
"markkeys @=L=H" if you do not want to use the `H' or `L' commands
any longer. As shown in this example, multiple keys can be assigned
to one function in a single statement.
maxwin num
Set the maximum window number screen will create. Doesn't affect
already existing windows. The number can be increased only when there
are no existing windows.
meta
Insert the command character (C-a) in the current window's input
stream.
monitor [on|off]
Toggles activity monitoring of windows. When monitoring is turned on
and an affected window is switched into the background, you will
receive the activity notification message in the status line at the
first sign of output and the window will also be marked with an `@'
in the window-status display. Monitoring is initially off for all
windows.
mousetrack [on|off]
This command determines whether screen will watch for mouse clicks.
When this command is enabled, regions that have been split in various
ways can be selected by pointing to them with a mouse and left-
clicking them. Without specifying on or off, the current state is
displayed. The default state is determined by the "defmousetrack"
command.
msgminwait sec
Defines the time screen delays a new message when one message is
currently displayed. The default is 1 second.
msgwait sec
Defines the time a message is displayed if screen is not disturbed by
other activity. The default is 5 seconds.
multiuser on|off
Switch between singleuser and multiuser mode. Standard screen
operation is singleuser. In multiuser mode the commands `acladd',
`aclchg', `aclgrp' and `acldel' can be used to enable (and disable)
other users accessing this screen session.
nethack on|off
Changes the kind of error messages used by screen. When you are
familiar with the game "nethack", you may enjoy the nethack-style
messages which will often blur the facts a little, but are much
funnier to read. Anyway, standard messages often tend to be unclear
as well.
This option is only available if screen was compiled with the NETHACK
flag defined. The default setting is then determined by the presence
of the environment variable $NETHACKOPTIONS and the file ~/.nethackrc
- if either one is present, the default is on.
next
Switch to the next window. This command can be used repeatedly to
cycle through the list of windows.
nonblock [on|off|numsecs]
Tell screen how to deal with user interfaces (displays) that cease to
accept output. This can happen if a user presses ^S or a TCP/modem
connection gets cut but no hangup is received. If nonblock is off
(this is the default) screen waits until the display restarts to
accept the output. If nonblock is on, screen waits until the timeout
is reached (on is treated as 1s). If the display still doesn't
receive characters, screen will consider it "blocked" and stop
sending characters to it. If at some time it restarts to accept
characters, screen will unblock the display and redisplay the updated
window contents.
number [[+|-]n]
Change the current window's number. If the given number n is already
used by another window, both windows exchange their numbers. If no
argument is specified, the current window number (and title) is
shown. Using `+' or `-' will change the window's number by the
relative amount specified.
obuflimit [limit]
If the output buffer contains more bytes than the specified limit, no
more data will be read from the windows. The default value is 256. If
you have a fast display (like xterm), you can set it to some higher
value. If no argument is specified, the current setting is displayed.
only
Kill all regions but the current one.
other
Switch to the window displayed previously. If this window does no
longer exist, other has the same effect as next.
partial on|off
Defines whether the display should be refreshed (as with redisplay)
after switching to the current window. This command only affects the
current window. To immediately affect all windows use the allpartial
command. Default is `off', of course. This default is fixed, as
there is currently no defpartial command.
password [crypted_pw]
Present a crypted password in your ".screenrc" file and screen will
ask for it, whenever someone attempts to resume a detached. This is
useful if you have privileged programs running under screen and you
want to protect your session from reattach attempts by another user
masquerading as your uid (i.e. any superuser.) If no crypted
password is specified, screen prompts twice for typing a password and
places its encryption in the paste buffer. Default is `none', this
disables password checking.
paste [registers [dest_reg]]
Write the (concatenated) contents of the specified registers to the
stdin queue of the current window. The register '.' is treated as the
paste buffer. If no parameter is given the user is prompted for a
single register to paste. The paste buffer can be filled with the
copy, history and readbuf commands. Other registers can be filled
with the register, readreg and paste commands. If paste is called
with a second argument, the contents of the specified registers is
pasted into the named destination register rather than the window. If
'.' is used as the second argument, the displays paste buffer is the
destination. Note, that "paste" uses a wide variety of resources:
Whenever a second argument is specified no current window is needed.
When the source specification only contains registers (not the paste
buffer) then there need not be a current display (terminal attached),
as the registers are a global resource. The paste buffer exists once
for every user.
pastefont [on|off]
Tell screen to include font information in the paste buffer. The
default is not to do so. This command is especially useful for multi
character fonts like kanji.
pow_break
Reopen the window's terminal line and send a break condition. See
`break'.
pow_detach
Power detach. Mainly the same as detach, but also sends a HANGUP
signal to the parent process of screen. CAUTION: This will result in
a logout, when screen was started from your login-shell.
pow_detach_msg [message]
The message specified here is output whenever a `Power detach' was
performed. It may be used as a replacement for a logout message or to
reset baud rate, etc. Without parameter, the current message is
shown.
prev
Switch to the window with the next lower number. This command can be
used repeatedly to cycle through the list of windows.
printcmd [cmd]
If cmd is not an empty string, screen will not use the terminal
capabilities "po/pf" if it detects an ansi print sequence ESC [ 5 i,
but pipe the output into cmd. This should normally be a command like
"lpr" or "'cat > /tmp/scrprint'". printcmd without a command
displays the current setting. The ansi sequence ESC \ ends printing
and closes the pipe.
Warning: Be careful with this command! If other user have write
access to your terminal, they will be able to fire off print
commands.
process [key]
Stuff the contents of the specified register into screen's input
queue. If no argument is given you are prompted for a register name.
The text is parsed as if it had been typed in from the user's
keyboard. This command can be used to bind multiple actions to a
single key.
quit
Kill all windows and terminate screen. Note that on VT100-style
terminals the keys C-4 and C-\ are identical. This makes the default
bindings dangerous: Be careful not to type C-a C-4 when selecting
window no. 4. Use the empty bind command (as in "bind '^\'") to
remove a key binding.
readbuf [encoding] [filename]
Reads the contents of the specified file into the paste buffer. You
can tell screen the encoding of the file via the -e option. If no
file is specified, the screen-exchange filename is used. See also
"bufferfile" command.
readreg [encoding] [register [filename]]
Does one of two things, dependent on number of arguments: with zero
or one arguments it duplicates the paste buffer contents into the
register specified or entered at the prompt. With two arguments it
reads the contents of the named file into the register, just as
readbuf reads the screen-exchange file into the paste buffer. You
can tell screen the encoding of the file via the -e option. The
following example will paste the system's password file into the
screen window (using register p, where a copy remains):
C-a : readreg p /etc/passwd
C-a : paste p
redisplay
Redisplay the current window. Needed to get a full redisplay when in
partial redraw mode.
register [-eencoding]key-string
Save the specified string to the register key. The encoding of the
string can be specified via the -e option. See also the "paste"
command.
remove
Kill the current region. This is a no-op if there is only one region.
removebuf
Unlinks the screen-exchange file used by the commands "writebuf" and
"readbuf".
rendition bell | monitor | silence | so attr [ color ]
Change the way screen renders the titles of windows that have monitor
or bell flags set in caption or hardstatus or windowlist. See the
"STRING ESCAPES" chapter for the syntax of the modifiers. The
default for monitor is currently "=b " (bold, active colors), for
bell "=ub " (underline, bold and active colors), and "=u " for
silence.
reset
Reset the virtual terminal to its "power-on" values. Useful when
strange settings (like scroll regions or graphics character set) are
left over from an application.
resize [-h|-v|-b|-l|-p] [[+|-] n[%] |=|max|min|_|0]
Resize the current region. The space will be removed from or added to
the surrounding regions depending on the order of the splits. The
available options for resizing are `-h'(horizontal), `-v'(vertical),
`-b'(both), `-l'(local to layer), and `-p'(perpendicular). Horizontal
resizes will add or remove width to a region, vertical will add or
remove height, and both will add or remove size from both dimensions.
Local and perpendicular are similar to horizontal and vertical, but
they take in account of how a region was split. If a region's last
split was horizontal, a local resize will work like a vertical
resize. If a region's last split was vertical, a local resize will
work like a horizontal resize. Perpendicular resizes work in opposite
of local resizes. If no option is specified, local is the default.
The amount of lines to add or remove can be expressed a couple of
different ways. By specifying a number n by itself will resize the
region by that absolute amount. You can specify a relative amount by
prefixing a plus `+' or minus `-' to the amount, such as adding +n
lines or removing -n lines. Resizing can also be expressed as an
absolute or relative percentage by postfixing a percent sign `%'.
Using zero `0' is a synonym for `min' and using an underscore `_' is
a synonym for `max'.
Some examples are:
resize +N
increase current region by N
resize -N
decrease current region by N
resize N
set current region to N
resize 20%
set current region to 20% of original size
resize +20%
increase current region by 20%
resize -b =
make all windows equally
resize max
maximize current region
resize min
minimize current region
Without any arguments, screen will prompt for how you would like to
resize the current region.
See "focusminsize" if you want to restrict the minimun size a region
can have.
screen [-opts] [n] [cmd [args]|//group]
Establish a new window. The flow-control options (-f, -fn and -fa),
title (a.k.a.) option (-t), login options (-l and -ln) , terminal
type option (-T <term>), the all-capability-flag (-a) and scrollback
option (-h <num>) may be specified with each command. The option
(-M) turns monitoring on for this window. The option (-L) turns
output logging on for this window. If an optional number n in the
range 0..MAXWIN-1 is given, the window number n is assigned to the
newly created window (or, if this number is already in-use, the next
available number). If a command is specified after "screen", this
command (with the given arguments) is started in the window;
otherwise, a shell is created. If //group is supplied, a container-
type window is created in which other windows may be created inside
it.
Thus, if your ".screenrc" contains the lines
# example for .screenrc:
screen 1
screen -fn -t foobar -L 2 telnet foobar
screen creates a shell window (in window #1) and a window with a
TELNET connection to the machine foobar (with no flow-control using
the title "foobar" in window #2) and will write a logfile
("screenlog.2") of the telnet session. Note, that unlike previous
versions of screen no additional default window is created when
"screen" commands are included in your ".screenrc" file. When the
initialization is completed, screen switches to the last window
specified in your .screenrc file or, if none, opens a default window
#0.
Screen has built in some functionality of "cu" and "telnet". See
also chapter "WINDOW TYPES".
scrollback num
Set the size of the scrollback buffer for the current windows to num
lines. The default scrollback is 100 lines. See also the
"defscrollback" command and use "info" to view the current setting.
To access and use the contents in the scrollback buffer, use the
"copy" command.
select [WindowID]
Switch to the window identified by WindowID. This can be a prefix of
a window title (alphanumeric window name) or a window number. The
parameter is optional and if omitted, you get prompted for an
identifier. When a new window is established, the first available
number is assigned to this window. Thus, the first window can be
activated by "select 0". The number of windows is limited at
compile-time by the MAXWIN configuration parameter (which defaults to
40). There are two special WindowIDs, "-" selects the internal blank
window and "." selects the current window. The latter is useful if
used with screen's "-X" option.
sessionname [name]
Rename the current session. Note, that for "screen -list" the name
shows up with the process-id prepended. If the argument "name" is
omitted, the name of this session is displayed. Caution: The $STY
environment variables will still reflect the old name in pre-existing
shells. This may result in confusion. Use of this command is
generally discouraged. Use the "-S" command-line option if you want
to name a new session. The default is constructed from the tty and
host names.
setenv [var [string]]
Set the environment variable var to value string. If only var is
specified, the user will be prompted to enter a value. If no
parameters are specified, the user will be prompted for both variable
and value. The environment is inherited by all subsequently forked
shells.
setsid [on|off]
Normally screen uses different sessions and process groups for the
windows. If setsid is turned off, this is not done anymore and all
windows will be in the same process group as the screen backend
process. This also breaks job-control, so be careful. The default is
on, of course. This command is probably useful only in rare
circumstances.
shell command
Set the command to be used to create a new shell. This overrides the
value of the environment variable $SHELL. This is useful if you'd
like to run a tty-enhancer which is expecting to execute the program
specified in $SHELL. If the command begins with a '-' character, the
shell will be started as a login-shell. Typical shells do only
minimal initialization when not started as a login-shell. E.g. Bash
will not read your "~/.bashrc" unless it is a login-shell.
shelltitle title
Set the title for all shells created during startup or by the C-A C-c
command. For details about what a title is, see the discussion
entitled "TITLES (naming windows)".
silence [on|off|sec]
Toggles silence monitoring of windows. When silence is turned on and
an affected window is switched into the background, you will receive
the silence notification message in the status line after a specified
period of inactivity (silence). The default timeout can be changed
with the `silencewait' command or by specifying a number of seconds
instead of `on' or `off'. Silence is initially off for all windows.
silencewait sec
Define the time that all windows monitored for silence should wait
before displaying a message. Default 30 seconds.
sleep num
This command will pause the execution of a .screenrc file for num
seconds. Keyboard activity will end the sleep. It may be used to
give users a chance to read the messages output by "echo".
slowpaste msec
Define the speed at which text is inserted into the current window by
the paste ("C-a ]") command. If the slowpaste value is nonzero text
is written character by character. screen will make a pause of msec
milliseconds after each single character write to allow the
application to process its input. Only use slowpaste if your
underlying system exposes flow control problems while pasting large
amounts of text.
sort
Sort the windows in alphabetical order of the window tiles.
source file
Read and execute commands from file file. Source commands may be
nested to a maximum recursion level of ten. If file is not an
absolute path and screen is already processing a source command, the
parent directory of the running source command file is used to search
for the new command file before screen's current directory.
Note that termcap/terminfo/termcapinfo commands only work at startup
and reattach time, so they must be reached via the default screenrc
files to have an effect.
sorendition [attr[color]]
This command is deprecated. See "rendition so" instead.
split[-v]
Split the current region into two new ones. All regions on the
display are resized to make room for the new region. The blank window
is displayed in the new region. The default is to create a horizontal
split, putting the new regions on the top and bottom of each other.
Using `-v' will create a vertical split, causing the new regions to
appear side by side of each other. Use the "remove" or the "only"
command to delete regions. Use "focus" to toggle between regions.
When a region is split opposite of how it was previously split (that
is, vertical then horizontal or horizontal then vertical), a new
layer is created. The layer is used to group together the regions
that are split the same. Normally, as a user, you should not see nor
have to worry about layers, but they will affect how some commands
("focus" and "resize") behave.
With this current implementation of screen, scrolling data will
appear much slower in a vertically split region than one that is not.
This should be taken into consideration if you need to use system
commands such as "cat" or "tail -f".
startup_message on|off
Select whether you want to see the copyright notice during startup.
Default is `on', as you probably noticed.
status [top|up|down|bottom] [left|right]
The status window by default is in bottom-left corner. This command
can move status messages to any corner of the screen. top is the same
as up, down is the same as bottom.
stuff [string]
Stuff the string string in the input buffer of the current window.
This is like the "paste" command but with much less overhead.
Without a parameter, screen will prompt for a string to stuff. You
cannot paste large buffers with the "stuff" command. It is most
useful for key bindings. See also "bindkey".
su [username [password [password2]]]
Substitute the user of a display. The command prompts for all
parameters that are omitted. If passwords are specified as
parameters, they have to be specified un-crypted. The first password
is matched against the systems passwd database, the second password
is matched against the screen password as set with the commands
"acladd" or "password". "Su" may be useful for the screen
administrator to test multiuser setups. When the identification
fails, the user has access to the commands available for user nobody.
These are "detach", "license", "version", "help" and "displays".
suspend
Suspend screen. The windows are in the `detached' state, while
screen is suspended. This feature relies on the shell being able to
do job control.
term term
In each window's environment screen opens, the $TERM variable is set
to "screen" by default. But when no description for "screen" is
installed in the local termcap or terminfo data base, you set $TERM
to - say - "vt100". This won't do much harm, as screen is VT100/ANSI
compatible. The use of the "term" command is discouraged for non-
default purpose. That is, one may want to specify special $TERM
settings (e.g. vt100) for the next "screen rlogin othermachine"
command. Use the command "screen -T vt100 rlogin othermachine" rather
than setting and resetting the default.
termcap term terminal-tweaks[window-tweaks]terminfo term terminal-tweaks[window-tweaks]termcapinfo term terminal-tweaks[window-tweaks]
Use this command to modify your terminal's termcap entry without
going through all the hassles involved in creating a custom termcap
entry. Plus, you can optionally customize the termcap generated for
the windows. You have to place these commands in one of the screenrc
startup files, as they are meaningless once the terminal emulator is
booted.
If your system uses the terminfo database rather than termcap, screen
will understand the `terminfo' command, which has the same effects as
the `termcap' command. Two separate commands are provided, as there
are subtle syntactic differences, e.g. when parameter interpolation
(using `%') is required. Note that termcap names of the capabilities
have to be used with the `terminfo' command.
In many cases, where the arguments are valid in both terminfo and
termcap syntax, you can use the command `termcapinfo', which is just
a shorthand for a pair of `termcap' and `terminfo' commands with
identical arguments.
The first argument specifies which terminal(s) should be affected by
this definition. You can specify multiple terminal names by
separating them with `|'s. Use `*' to match all terminals and `vt*'
to match all terminals that begin with "vt".
Each tweak argument contains one or more termcap defines (separated
by `:'s) to be inserted at the start of the appropriate termcap
entry, enhancing it or overriding existing values. The first tweak
modifies your terminal's termcap, and contains definitions that your
terminal uses to perform certain functions. Specify a null string to
leave this unchanged (e.g. ''). The second (optional) tweak modifies
all the window termcaps, and should contain definitions that screen
understands (see the "VIRTUAL TERMINAL" section).
Some examples:
termcap xterm* LP:hs@
Informs screen that all terminals that begin with `xterm' have firm
auto-margins that allow the last position on the screen to be updated
(LP), but they don't really have a status line (no 'hs' - append `@'
to turn entries off). Note that we assume `LP' for all terminal
names that start with "vt", but only if you don't specify a termcap
command for that terminal.
termcap vt* LP
termcap vt102|vt220 Z0=\E[?3h:Z1=\E[?3l
Specifies the firm-margined `LP' capability for all terminals that
begin with `vt', and the second line will also add the escape-
sequences to switch into (Z0) and back out of (Z1) 132-character-per-
line mode if this is a VT102 or VT220. (You must specify Z0 and Z1
in your termcap to use the width-changing commands.)
termcap vt100 "" l0=PF1:l1=PF2:l2=PF3:l3=PF4
This leaves your vt100 termcap alone and adds the function key labels
to each window's termcap entry.
termcap h19|z19 am@:im=\E@:ei=\EO dc=\E[P
Takes a h19 or z19 termcap and turns off auto-margins (am@) and
enables the insert mode (im) and end-insert (ei) capabilities (the
`@' in the `im' string is after the `=', so it is part of the
string). Having the `im' and `ei' definitions put into your
terminal's termcap will cause screen to automatically advertise the
character-insert capability in each window's termcap. Each window
will also get the delete-character capability (dc) added to its
termcap, which screen will translate into a line-update for the
terminal (we're pretending it doesn't support character deletion).
If you would like to fully specify each window's termcap entry, you
should instead set the $SCREENCAP variable prior to running screen.
See the discussion on the "VIRTUAL TERMINAL" in this manual, and the
termcap(5) man page for more information on termcap definitions.
title [windowtitle]
Set the name of the current window to windowtitle. If no name is
specified, screen prompts for one. This command was known as `aka' in
previous releases.
truecolor [on|off]
Enables truecolor support. Currently autodetection of truecolor
support cannot be done reliably, as such it's left to user to enable.
Default is off. Known terminals that may support it are: iTerm2,
Konsole, st. Xterm includes support for truecolor escapes but
converts them back to indexed 256 color space.
unbindall
Unbind all the bindings. This can be useful when screen is used
solely for its detaching abilities, such as when letting a console
application run as a daemon. If, for some reason, it is necessary to
bind commands after this, use 'screen -X'.
unsetenv var
Unset an environment variable.
utf8 [on|off[on|off]]
Change the encoding used in the current window. If utf8 is enabled,
the strings sent to the window will be UTF-8 encoded and vice versa.
Omitting the parameter toggles the setting. If a second parameter is
given, the display's encoding is also changed (this should rather be
done with screen's "-U" option). See also "defutf8", which changes
the default setting of a new window.
vbell [on|off]
Sets the visual bell setting for this window. Omitting the parameter
toggles the setting. If vbell is switched on, but your terminal does
not support a visual bell, a `vbell-message' is displayed in the
status line when the bell character (^G) is received. Visual bell
support of a terminal is defined by the termcap variable `vb'
(terminfo: 'flash').
Per default, vbell is off, thus the audible bell is used. See also
`bell_msg'.
vbell_msg [message]
Sets the visual bell message. message is printed to the status line
if the window receives a bell character (^G), vbell is set to "on",
but the terminal does not support a visual bell. The default message
is "Wuff, Wuff!!". Without a parameter, the current message is
shown.
vbellwait sec
Define a delay in seconds after each display of screen's visual bell
message. The default is 1 second.
verbose [on|off]
If verbose is switched on, the command name is echoed, whenever a
window is created (or resurrected from zombie state). Default is off.
Without a parameter, the current setting is shown.
version
Print the current version and the compile date in the status line.
wall message
Write a message to all displays. The message will appear in the
terminal's status line.
width [-w|-d] [cols [lines]]
Toggle the window width between 80 and 132 columns or set it to cols
columns if an argument is specified. This requires a capable
terminal and the termcap entries "Z0" and "Z1". See the "termcap"
command for more information. You can also specify a new height if
you want to change both values. The -w option tells screen to leave
the display size unchanged and just set the window size, -d vice
versa.
windowlist [-b] [-m] [-g]
windowlist string [string]
windowlist title [title]
Display all windows in a table for visual window selection. If
screen was in a window group, screen will back out of the group and
then display the windows in that group. If the -b option is given,
screen will switch to the blank window before presenting the list, so
that the current window is also selectable. The -m option changes
the order of the windows, instead of sorting by window numbers screen
uses its internal most-recently-used list. The -g option will show
the windows inside any groups in that level and downwards.
The following keys are used to navigate in "windowlist":
─────────────────────────────────────────────────────────────────────
k, C-p, or up Move up one line.
─────────────────────────────────────────────────────────────────────
j, C-n, or down Move down one line.
─────────────────────────────────────────────────────────────────────
C-g or escape Exit windowlist.
─────────────────────────────────────────────────────────────────────
C-a or home Move to the first line.
─────────────────────────────────────────────────────────────────────
C-e or end Move to the last line.
─────────────────────────────────────────────────────────────────────
C-u or C-d Move one half page up or down.
─────────────────────────────────────────────────────────────────────
C-b or C-f Move one full page up or down.
─────────────────────────────────────────────────────────────────────
0..9 Using the number keys, move to the selected line.
─────────────────────────────────────────────────────────────────────
mouseclick Move to the selected line. Available when
"mousetrack" is set to "on"
─────────────────────────────────────────────────────────────────────
/ Search.
─────────────────────────────────────────────────────────────────────
n Repeat search in the forward direction.
─────────────────────────────────────────────────────────────────────
N Repeat search in the backward direction.
─────────────────────────────────────────────────────────────────────
m Toggle MRU.
─────────────────────────────────────────────────────────────────────
g Toggle group nesting.
─────────────────────────────────────────────────────────────────────
a All window view.
─────────────────────────────────────────────────────────────────────
C-h or backspace Back out the group.
─────────────────────────────────────────────────────────────────────
, Switch numbers with the previous window.
─────────────────────────────────────────────────────────────────────
. Switch numbers with the next window.
─────────────────────────────────────────────────────────────────────
K Kill that window.
─────────────────────────────────────────────────────────────────────
space or enter Select that window.
─────────────────────────────────────────────────────────────────────
The table format can be changed with the string and title option, the
title is displayed as table heading, while the lines are made by
using the string setting. The default setting is "Num Name%=Flags"
for the title and "%3n %t%=%f" for the lines. See the "STRING
ESCAPES" chapter for more codes (e.g. color settings).
"Windowlist" needs a region size of at least 10 characters wide and 6
characters high in order to display.
windows [ string ]
Uses the message line to display a list of all the windows. Each
window is listed by number with the name of process that has been
started in the window (or its title); the current window is marked
with a `*'; the previous window is marked with a `-'; all the windows
that are "logged in" are marked with a `$'; a background window that
has received a bell is marked with a `!'; a background window that is
being monitored and has had activity occur is marked with an `@'; a
window which has output logging turned on is marked with `(L)';
windows occupied by other users are marked with `&'; windows in the
zombie state are marked with `Z'. If this list is too long to fit on
the terminal's status line only the portion around the current window
is displayed. The optional string parameter follows the "STRING
ESCAPES" format. If string parameter is passed, the output size is
unlimited. The default command without any parameter is limited to a
size of 1024 bytes.
wrap [on|off]
Sets the line-wrap setting for the current window. When line-wrap is
on, the second consecutive printable character output at the last
column of a line will wrap to the start of the following line. As an
added feature, backspace (^H) will also wrap through the left margin
to the previous line. Default is `on'. Without any options, the
state of wrap is toggled.
writebuf [-e encoding] [filename]
Writes the contents of the paste buffer to the specified file, or the
public accessible screen-exchange file if no filename is given. This
is thought of as a primitive means of communication between screen
users on the same host. If an encoding is specified the paste buffer
is recoded on the fly to match the encoding. The filename can be set
with the bufferfile command and defaults to "/tmp/screen-exchange".
writelock [on|off|auto]
In addition to access control lists, not all users may be able to
write to the same window at once. Per default, writelock is in `auto'
mode and grants exclusive input permission to the user who is the
first to switch to the particular window. When he leaves the window,
other users may obtain the writelock (automatically). The writelock
of the current window is disabled by the command "writelock off". If
the user issues the command "writelock on" he keeps the exclusive
write permission while switching to other windows.
xoffxon
Insert a CTRL-s / CTRL-q character to the stdin queue of the current
window.
zmodem [off|auto|catch|pass]
zmodem sendcmd [string]
zmodem recvcmd [string]
Define zmodem support for screen. Screen understands two different
modes when it detects a zmodem request: "pass" and "catch". If the
mode is set to "pass", screen will relay all data to the attacher
until the end of the transmission is reached. In "catch" mode screen
acts as a zmodem endpoint and starts the corresponding rz/sz
commands. If the mode is set to "auto", screen will use "catch" if
the window is a tty (e.g. a serial line), otherwise it will use
"pass".
You can define the templates screen uses in "catch" mode via the
second and the third form.
Note also that this is an experimental feature.
zombie [keys[onerror]]
Per default screen windows are removed from the window list as soon
as the windows process (e.g. shell) exits. When a string of two keys
is specified to the zombie command, `dead' windows will remain in the
list. The kill command may be used to remove such a window. Pressing
the first key in the dead window has the same effect. When pressing
the second key, screen will attempt to resurrect the window. The
process that was initially running in the window will be launched
again. Calling zombie without parameters will clear the zombie
setting, thus making windows disappear when their process exits.
As the zombie-setting is manipulated globally for all windows, this
command should probably be called defzombie, but it isn't.
Optionally you can put the word "onerror" after the keys. This will
cause screen to monitor exit status of the process running in the
window. If it exits normally ('0'), the window disappears. Any other
exit value causes the window to become a zombie.
zombie_timeout[seconds]
Per default screen windows are removed from the window list as soon
as the windows process (e.g. shell) exits. If zombie keys are defined
(compare with above zombie command), it is possible to also set a
timeout when screen tries to automatically reconnect a dead screen
window.

Screen displays informational messages and other diagnostics in a
message line. While this line is distributed to appear at the bottom
of the screen, it can be defined to appear at the top of the screen
during compilation. If your terminal has a status line defined in
its termcap, screen will use this for displaying its messages,
otherwise a line of the current screen will be temporarily
overwritten and output will be momentarily interrupted. The message
line is automatically removed after a few seconds delay, but it can
also be removed early (on terminals without a status line) by
beginning to type.
The message line facility can be used by an application running in
the current window by means of the ANSI Privacy message control
sequence. For instance, from within the shell, try something like:
echo '<esc>^Hello world from window '$WINDOW'<esc>\\'
where '<esc>' is an escape, '^' is a literal up-arrow, and '\\' turns
into a single backslash.

Screen provides three different window types. New windows are created
with screen's screen command (see also the entry in chapter
"CUSTOMIZATION"). The first parameter to the screen command defines
which type of window is created. The different window types are all
special cases of the normal type. They have been added in order to
allow screen to be used efficiently as a console multiplexer with 100
or more windows.
· The normal window contains a shell (default, if no parameter is
given) or any other system command that could be executed from a
shell (e.g. slogin, etc...)
· If a tty (character special device) name (e.g. "/dev/ttya") is
specified as the first parameter, then the window is directly
connected to this device. This window type is similar to "screen
cu -l /dev/ttya". Read and write access is required on the device
node, an exclusive open is attempted on the node to mark the
connection line as busy. An optional parameter is allowed
consisting of a comma separated list of flags in the notation used
by stty(1):
<baud_rate>
Usually 300, 1200, 9600 or 19200. This affects transmission
as well as receive speed.
cs8 or cs7
Specify the transmission of eight (or seven) bits per byte.
ixon or -ixon
Enables (or disables) software flow-control (CTRL-S/CTRL-Q)
for sending data.
ixoff or -ixoff
Enables (or disables) software flow-control for receiving
data.
istrip or -istrip
Clear (or keep) the eight bit in each received byte.
You may want to specify as many of these options as applicable.
Unspecified options cause the terminal driver to make up the
parameter values of the connection. These values are system
dependent and may be in defaults or values saved from a previous
connection.
For tty windows, the info command shows some of the modem control
lines in the status line. These may include `RTS', `CTS', 'DTR',
`DSR', `CD' and more. This depends on the available ioctl()'s and
system header files as well as the on the physical capabilities of
the serial board. Signals that are logical low (inactive) have
their name preceded by an exclamation mark (!), otherwise the
signal is logical high (active). Signals not supported by the
hardware but available to the ioctl() interface are usually shown
low.
When the CLOCAL status bit is true, the whole set of modem signals
is placed inside curly braces ({ and }). When the CRTSCTS or
TIOCSOFTCAR bit is set, the signals `CTS' or `CD' are shown in
parenthesis, respectively.
For tty windows, the command break causes the Data transmission
line (TxD) to go low for a specified period of time. This is
expected to be interpreted as break signal on the other side. No
data is sent and no modem control line is changed when a break is
issued.
· If the first parameter is "//telnet", the second parameter is
expected to be a host name, and an optional third parameter may
specify a TCP port number (default decimal 23). Screen will
connect to a server listening on the remote host and use the
telnet protocol to communicate with that server.
For telnet windows, the command info shows details about the
connection in square brackets ([ and ]) at the end of the status
line.
b BINARY. The connection is in binary mode.
e ECHO. Local echo is disabled.
c SGA. The connection is in `character mode' (default:
`line mode').
t TTYPE. The terminal type has been requested by the
remote host. Screen sends the name "screen" unless
instructed otherwise (see also the command `term').
w NAWS. The remote site is notified about window size
changes.
f LFLOW. The remote host will send flow control
information. (Ignored at the moment.)
Additional flags for debugging are x, t and n (XDISPLOC,
TSPEED and NEWENV).
For telnet windows, the command break sends the telnet code
IAC BREAK (decimal 243) to the remote host.
This window type is only available if screen was compiled with
the ENABLE_TELNET option defined.

Screen provides an escape mechanism to insert information like the
current time into messages or file names. The escape character is '%'
with one exception: inside of a window's hardstatus '^%' ('^E') is
used instead.
Here is the full list of supported escapes:
% the escape character itself
E sets %? to true if the escape character has been pressed.
f flags of the window, see "windows" for meanings of the various
flags
F sets %? to true if the window has the focus
h hardstatus of the window
H hostname of the system
n window number
P sets %? to true if the current region is in copy/paste mode
S session name
s window size
t window title
u all other users on this window
w all window numbers and names. With '-' qualifier: up to the
current window; with '+' qualifier: starting with the window
after the current one.
W all window numbers and names except the current one
x the executed command including arguments running in this
windows
X the executed command without arguments running in this windows
? the part to the next '%?' is displayed only if a '%' escape
inside the part expands to a non-empty string
: else part of '%?'
= pad the string to the display's width (like TeX's hfill). If a
number is specified, pad to the percentage of the window's
width. A '0' qualifier tells screen to treat the number as
absolute position. You can specify to pad relative to the
last absolute pad position by adding a '+' qualifier or to pad
relative to the right margin by using '-'. The padding
truncates the string if the specified position lies before the
current position. Add the 'L' qualifier to change this.
< same as '%=' but just do truncation, do not fill with spaces
> mark the current text position for the next truncation. When
screen needs to do truncation, it tries to do it in a way that
the marked position gets moved to the specified percentage of
the output area. (The area starts from the last absolute pad
position and ends with the position specified by the
truncation operator.) The 'L' qualifier tells screen to mark
the truncated parts with '...'.
{ attribute/color modifier string terminated by the next "}"
` Substitute with the output of a 'backtick' command. The length
qualifier is misused to identify one of the commands.
The 'c' and 'C' escape may be qualified with a '0' to make screen use
zero instead of space as fill character. The '0' qualifier also makes
the '=' escape use absolute positions. The 'n' and '=' escapes
understand a length qualifier (e.g. '%3n'), 'D' and 'M' can be
prefixed with 'L' to generate long names, 'w' and 'W' also show the
window flags if 'L' is given.
An attribute/color modifier is used to change the attributes or the
color settings. Its format is "[attribute modifier] [color
description]". The attribute modifier must be prefixed by a change
type indicator if it can be confused with a color description. The
following change types are known:
+ add the specified set to the current attributes
- remove the set from the current attributes
! invert the set in the current attributes
= change the current attributes to the specified set
The attribute set can either be specified as a hexadecimal number or
a combination of the following letters:
d dim
u underline
b bold
r reverse
s standout
B blinking
The old format of specifying colors by letters (k,r,g,y,b,m,c,w) is
now deprecated. Colors are coded as 0-7 for basic ANSI, 0-255 for 256
color mode, or for truecolor, either a hexadecimal code starting with
x, or HTML notation as either 3 or 6 hexadecimal digits. Foreground
and background are specified by putting a semicolon between them. Ex:
"#FFF;#000" or "i7;0" is white on a black background.
The following numbers are for basic ANSI:
0 black
1 red
2 green
3 yellow
4 blue
5 magenta
6 cyan
7 white
You can also use the pseudo-color 'i' to set just the brightness and
leave the color unchanged.
As a special case, "%{-}" restores the attributes and colors that
were set before the last change was made (i.e., pops one level of the
color-change stack).
Examples:
"i2" set color to bright green
"+b r" use bold red
"#F00;FFA"
write in bright red color on a pale yellow background.
%-Lw%{#AAA;#006}%50>%n%f* %t%{-}%+Lw%<
The available windows centered at the current window and
truncated to the available width. The current window is
displayed white on blue. This can be used with "hardstatus
alwayslastline".
%?%F%{;2}%?%3n %t%? [%h]%?
The window number and title and the window's hardstatus, if
one is set. Also use a red background if this is the active
focus. Useful for "caption string".

Each window has a flow-control setting that determines how screen
deals with the XON and XOFF characters (and perhaps the interrupt
character). When flow-control is turned off, screen ignores the XON
and XOFF characters, which allows the user to send them to the
current program by simply typing them (useful for the emacs editor,
for instance). The trade-off is that it will take longer for output
from a "normal" program to pause in response to an XOFF. With flow-
control turned on, XON and XOFF characters are used to immediately
pause the output of the current window. You can still send these
characters to the current program, but you must use the appropriate
two-character screen commands (typically "C-a q" (xon) and "C-a s"
(xoff)). The xon/xoff commands are also useful for typing C-s and C-
q past a terminal that intercepts these characters.
Each window has an initial flow-control value set with either the -f
option or the "defflow" .screenrc command. Per default the windows
are set to automatic flow-switching. It can then be toggled between
the three states 'fixed on', 'fixed off' and 'automatic'
interactively with the "flow" command bound to "C-a f".
The automatic flow-switching mode deals with flow control using the
TIOCPKT mode (like "rlogin" does). If the tty driver does not support
TIOCPKT, screen tries to find out the right mode based on the current
setting of the application keypad - when it is enabled, flow-control
is turned off and visa versa. Of course, you can still manipulate
flow-control manually when needed.
If you're running with flow-control enabled and find that pressing
the interrupt key (usually C-c) does not interrupt the display until
another 6-8 lines have scrolled by, try running screen with the
"interrupt" option (add the "interrupt" flag to the "flow" command in
your .screenrc, or use the -i command-line option). This causes the
output that screen has accumulated from the interrupted program to be
flushed. One disadvantage is that the virtual terminal's memory
contains the non-flushed version of the output, which in rare cases
can cause minor inaccuracies in the output. For example, if you
switch screens and return, or update the screen with "C-a l" you
would see the version of the output you would have gotten without
"interrupt" being on. Also, you might need to turn off flow-control
(or use auto-flow mode to turn it off automatically) when running a
program that expects you to type the interrupt character as input, as
it is possible to interrupt the output of the virtual terminal to
your physical terminal when flow-control is enabled. If this
happens, a simple refresh of the screen with "C-a l" will restore it.
Give each mode a try, and use whichever mode you find more
comfortable.

You can customize each window's name in the window display (viewed
with the "windows" command (C-a w)) by setting it with one of the
title commands. Normally the name displayed is the actual command
name of the program created in the window. However, it is sometimes
useful to distinguish various programs of the same name or to change
the name on-the-fly to reflect the current state of the window.
The default name for all shell windows can be set with the
"shelltitle" command in the .screenrc file, while all other windows
are created with a "screen" command and thus can have their name set
with the -t option. Interactively, there is the title-string escape-
sequence (<esc>kname<esc>\) and the "title" command (C-a A). The
former can be output from an application to control the window's name
under software control, and the latter will prompt for a name when
typed. You can also bind pre-defined names to keys with the "title"
command to set things quickly without prompting. Changing title by
this escape sequence can be controlled by defdynamictitle and
dynamictitle commands.
Finally, screen has a shell-specific heuristic that is enabled by
setting the window's name to "search|name" and arranging to have a
null title escape-sequence output as a part of your prompt. The
search portion specifies an end-of-prompt search string, while the
name portion specifies the default shell name for the window. If the
name ends in a `:' screen will add what it believes to be the current
command running in the window to the end of the window's shell name
(e.g. "name:cmd"). Otherwise the current command name supersedes the
shell name while it is running.
Here's how it works: you must modify your shell prompt to output a
null title-escape-sequence (<esc>k<esc>\) as a part of your prompt.
The last part of your prompt must be the same as the string you
specified for the search portion of the title. Once this is set up,
screen will use the title-escape-sequence to clear the previous
command name and get ready for the next command. Then, when a
newline is received from the shell, a search is made for the end of
the prompt. If found, it will grab the first word after the matched
string and use it as the command name. If the command name begins
with either '!', '%', or '^' screen will use the first word on the
following line (if found) in preference to the just-found name. This
helps csh users get better command names when using job control or
history recall commands.
Here's some .screenrc examples:
screen -t top 2 nice top
Adding this line to your .screenrc would start a nice-d version of
the "top" command in window 2 named "top" rather than "nice".
shelltitle '> |csh'
screen 1
These commands would start a shell with the given shelltitle. The
title specified is an auto-title that would expect the prompt and the
typed command to look something like the following:
/usr/joe/src/dir> trn
(it looks after the '> ' for the command name). The window status
would show the name "trn" while the command was running, and revert
to "csh" upon completion.
bind R screen -t '% |root:' su
Having this command in your .screenrc would bind the key sequence "C-
a R" to the "su" command and give it an auto-title name of "root:".
For this auto-title to work, the screen could look something like
this:
% !em
emacs file.c
Here the user typed the csh history command "!em" which ran the
previously entered "emacs" command. The window status would show
"root:emacs" during the execution of the command, and revert to
simply "root:" at its completion.
bind o title
bind E title ""
bind u title (unknown)
The first binding doesn't have any arguments, so it would prompt you
for a title when you type "C-a o". The second binding would clear an
auto-title's current setting (C-a E). The third binding would set
the current window's title to "(unknown)" (C-a u).
One thing to keep in mind when adding a null title-escape-sequence to
your prompt is that some shells (like the csh) count all the non-
control characters as part of the prompt's length. If these
invisible characters aren't a multiple of 8 then backspacing over a
tab will result in an incorrect display. One way to get around this
is to use a prompt like this:
set prompt='^[[0000m^[k^[\% '
The escape-sequence "<esc>[0000m" not only normalizes the character
attributes, but all the zeros round the length of the invisible
characters up to 8. Bash users will probably want to echo the escape
sequence in the PROMPT_COMMAND:
PROMPT_COMMAND='printf "\033k\033\134"'
(I used "\134" to output a `\' because of a bug in bash v1.04).

Each window in a screen session emulates a VT100 terminal, with some
extra functions added. The VT100 emulator is hard-coded, no other
terminal types can be emulated.
Usually screen tries to emulate as much of the VT100/ANSI standard as
possible. But if your terminal lacks certain capabilities, the
emulation may not be complete. In these cases screen has to tell the
applications that some of the features are missing. This is no
problem on machines using termcap, because screen can use the
$TERMCAP variable to customize the standard screen termcap.
But if you do a rlogin on another machine or your machine supports
only terminfo this method fails. Because of this, screen offers a way
to deal with these cases. Here is how it works:
When screen tries to figure out a terminal name for itself, it first
looks for an entry named "screen.<term>", where <term> is the
contents of your $TERM variable. If no such entry exists, screen
tries "screen" (or "screen-w" if the terminal is wide (132 cols or
more)). If even this entry cannot be found, "vt100" is used as a
substitute.
The idea is that if you have a terminal which doesn't support an
important feature (e.g. delete char or clear to EOS) you can build a
new termcap/terminfo entry for screen (named "screen.<dumbterm>") in
which this capability has been disabled. If this entry is installed
on your machines you are able to do a rlogin and still keep the
correct termcap/terminfo entry. The terminal name is put in the
$TERM variable of all new windows. Screen also sets the $TERMCAP
variable reflecting the capabilities of the virtual terminal
emulated. Notice that, however, on machines using the terminfo
database this variable has no effect. Furthermore, the variable
$WINDOW is set to the window number of each window.
The actual set of capabilities supported by the virtual terminal
depends on the capabilities supported by the physical terminal. If,
for instance, the physical terminal does not support underscore mode,
screen does not put the `us' and `ue' capabilities into the window's
$TERMCAP variable, accordingly. However, a minimum number of
capabilities must be supported by a terminal in order to run screen;
namely scrolling, clear screen, and direct cursor addressing (in
addition, screen does not run on hardcopy terminals or on terminals
that over-strike).
Also, you can customize the $TERMCAP value used by screen by using
the "termcap" .screenrc command, or by defining the variable
$SCREENCAP prior to startup. When the latter is defined, its value
will be copied verbatim into each window's $TERMCAP variable. This
can either be the full terminal definition, or a filename where the
terminal "screen" (and/or "screen-w") is defined.
Note that screen honors the "terminfo" .screenrc command if the
system uses the terminfo database rather than termcap.
When the boolean `G0' capability is present in the termcap entry for
the terminal on which screen has been called, the terminal emulation
of screen supports multiple character sets. This allows an
application to make use of, for instance, the VT100 graphics
character set or national character sets. The following control
functions from ISO 2022 are supported: lock shift G0 (SI), lock shiftG1 (SO), lock shift G2, lock shift G3, single shift G2, and singleshift G3. When a virtual terminal is created or reset, the ASCII
character set is designated as G0 through G3. When the `G0'
capability is present, screen evaluates the capabilities `S0', `E0',
and `C0' if present. `S0' is the sequence the terminal uses to enable
and start the graphics character set rather than SI. `E0' is the
corresponding replacement for SO. `C0' gives a character by character
translation string that is used during semi-graphics mode. This
string is built like the `acsc' terminfo capability.
When the `po' and `pf' capabilities are present in the terminal's
termcap entry, applications running in a screen window can send
output to the printer port of the terminal. This allows a user to
have an application in one window sending output to a printer
connected to the terminal, while all other windows are still active
(the printer port is enabled and disabled again for each chunk of
output). As a side-effect, programs running in different windows can
send output to the printer simultaneously. Data sent to the printer
is not displayed in the window. The info command displays a line
starting `PRIN' while the printer is active.
Screen maintains a hardstatus line for every window. If a window gets
selected, the display's hardstatus will be updated to match the
window's hardstatus line. If the display has no hardstatus the line
will be displayed as a standard screen message. The hardstatus line
can be changed with the ANSI Application Program Command (APC):
"ESC_<string>ESC\". As a convenience for xterm users the sequence
"ESC]0..2;<string>^G" is also accepted.
Some capabilities are only put into the $TERMCAP variable of the
virtual terminal if they can be efficiently implemented by the
physical terminal. For instance, `dl' (delete line) is only put into
the $TERMCAP variable if the terminal supports either delete line
itself or scrolling regions. Note that this may provoke confusion,
when the session is reattached on a different terminal, as the value
of $TERMCAP cannot be modified by parent processes.
The "alternate screen" capability is not enabled by default. Set the
altscreen .screenrc command to enable it.
The following is a list of control sequences recognized by screen.
"(V)" and "(A)" indicate VT100-specific and ANSI- or ISO-specific
functions, respectively.
ESC E Next Line
ESC D Index
ESC M Reverse Index
ESC H Horizontal Tab Set
ESC Z Send VT100 Identification String
ESC 7 (V) Save Cursor and Attributes
ESC 8 (V) Restore Cursor and Attributes
ESC [s (A) Save Cursor and Attributes
ESC [u (A) Restore Cursor and Attributes
ESC c Reset to Initial State
ESC g Visual Bell
ESC Pn p Cursor Visibility (97801)
Pn = 6 Invisible
Pn = 7 Visible
ESC = (V) Application Keypad Mode
ESC > (V) Numeric Keypad Mode
ESC # 8 (V) Fill Screen with E's
ESC \ (A) String Terminator
ESC ^ (A) Privacy Message String (Message Line)
ESC ! Global Message String (Message Line)
ESC k A.k.a. Definition String
ESC P (A) Device Control String. Outputs a string
directly to the host terminal without
interpretation.
ESC _ (A) Application Program Command (Hardstatus)
ESC ] 0 ; string ^G (A) Operating System Command (Hardstatus,
xterm title hack)
ESC ] 83 ; cmd ^G (A) Execute screen command. This only works if
multi-user support is compiled into
screen. The pseudo-user ":window:" is used
to check the access control list. Use
"addacl :window: -rwx #?" to create a user
with no rights and allow only the needed
commands.
Control-N (A) Lock Shift G1 (SO)
Control-O (A) Lock Shift G0 (SI)
ESC n (A) Lock Shift G2
ESC o (A) Lock Shift G3
ESC N (A) Single Shift G2
ESC O (A) Single Shift G3
ESC ( Pcs (A) Designate character set as G0
ESC ) Pcs (A) Designate character set as G1
ESC * Pcs (A) Designate character set as G2
ESC + Pcs (A) Designate character set as G3
ESC [ Pn ; Pn H Direct Cursor Addressing
ESC [ Pn ; Pn f same as above
ESC [ Pn J Erase in Display
Pn = None or 0 From Cursor to
End of Screen
Pn = 1 From Beginning
of Screen to
Cursor
Pn = 2 Entire Screen
ESC [ Pn K Erase in Line
Pn = None or 0 From Cursor to
End of Line
Pn = 1 From Beginning
of Line to
Cursor
Pn = 2 Entire Line
ESC [ Pn X Erase character
ESC [ Pn A Cursor Up
ESC [ Pn B Cursor Down
ESC [ Pn C Cursor Right
ESC [ Pn D Cursor Left
ESC [ Pn E Cursor next line
ESC [ Pn F Cursor previous line
ESC [ Pn G Cursor horizontal position
ESC [ Pn ` same as above
ESC [ Pn d Cursor vertical position
ESC [ Ps ;...; Ps m Select Graphic Rendition
Ps = None or 0 Default
Rendition
Ps = 1 Bold
Ps = 2 (A) Faint
Ps = 3 (A) Standout Mode
(ANSI:
Italicized)
Ps = 4 Underlined
Ps = 5 Blinking
Ps = 7 Negative Image
Ps = 22 (A) Normal
Intensity
Ps = 23 (A) Standout Mode
off (ANSI:
Italicized off)
Ps = 24 (A) Not Underlined
Ps = 25 (A) Not Blinking
Ps = 27 (A) Positive Image
Ps = 30 (A) Foreground
Black
Ps = 31 (A) Foreground Red
Ps = 32 (A) Foreground
Green
Ps = 33 (A) Foreground
Yellow
Ps = 34 (A) Foreground Blue
Ps = 35 (A) Foreground
Magenta
Ps = 36 (A) Foreground Cyan
Ps = 37 (A) Foreground
White
Ps = 39 (A) Foreground
Default
Ps = 40 (A) Background
Black
Ps = ...
Ps = 49 (A) Background
Default
ESC [ Pn g Tab Clear
Pn = None or 0 Clear Tab at
Current
Position
Pn = 3 Clear All Tabs
ESC [ Pn ; Pn r (V) Set Scrolling Region
ESC [ Pn I (A) Horizontal Tab
ESC [ Pn Z (A) Backward Tab
ESC [ Pn L (A) Insert Line
ESC [ Pn M (A) Delete Line
ESC [ Pn @ (A) Insert Character
ESC [ Pn P (A) Delete Character
ESC [ Pn S Scroll Scrolling Region Up
ESC [ Pn T Scroll Scrolling Region Down
ESC [ Pn ^ same as above
ESC [ Ps ;...; Ps h Set Mode
ESC [ Ps ;...; Ps l Reset Mode
Ps = 4 (A) Insert Mode
Ps = 20 (A) AutomaticLinefeed Mode
Ps = 34 Normal Cursor
Visibility
Ps = ?1 (V) Application
Cursor Keys
Ps = ?3 (V) Change Terminal
Width to 132
columns
Ps = ?5 (V) Reverse Video
Ps = ?6 (V) Origin Mode
Ps = ?7 (V) Wrap Mode
Ps = ?9 X10 mouse
tracking
Ps = ?25 (V) Visible Cursor
Ps = ?47 Alternate
Screen (old
xterm code)
Ps = ?1000 (V) VT200 mouse
tracking
Ps = ?1047 Alternate
Screen (new
xterm code)
Ps = ?1049 Alternate
Screen (new
xterm code)
ESC [ 5 i (A) Start relay to printer (ANSI Media Copy)
ESC [ 4 i (A) Stop relay to printer (ANSI Media Copy)
ESC [ 8 ; Ph ; Pw t Resize the window to `Ph' lines and `Pw'
columns (SunView special)
ESC [ c Send VT100 Identification String
ESC [ x Send Terminal Parameter Report
ESC [ > c Send VT220 Secondary Device Attributes
String
ESC [ 6 n Send Cursor Position Report

The following table describes all terminal capabilities that are
recognized by screen and are not in the termcap(5) manual. You can
place these capabilities in your termcap entries (in `/etc/termcap')
or use them with the commands `termcap', `terminfo' and `termcapinfo'
in your screenrc files. It is often not possible to place these
capabilities in the terminfo database.
LP (bool) Terminal has VT100 style margins (`magic margins'). Note
that this capability is obsolete because screen uses the
standard 'xn' instead.
Z0 (str) Change width to 132 columns.
Z1 (str) Change width to 80 columns.
WS (str) Resize display. This capability has the desired width
and height as arguments. SunView(tm) example:
'\E[8;%d;%dt'.
NF (bool) Terminal doesn't need flow control. Send ^S and ^Q
direct to the application. Same as 'flow off'. The
opposite of this capability is 'nx'.
G0 (bool) Terminal can deal with ISO 2022 font selection
sequences.
S0 (str) Switch charset 'G0' to the specified charset. Default is
'\E(%.'.
E0 (str) Switch charset 'G0' back to standard charset. Default is
'\E(B'.
C0 (str) Use the string as a conversion table for font '0'. See
the 'ac' capability for more details.
CS (str) Switch cursor-keys to application mode.
CE (str) Switch cursor-keys back to normal mode.
AN (bool) Turn on autonuke. See the 'autonuke' command for more
details.
OL (num) Set the output buffer limit. See the 'obuflimit' command
for more details.
KJ (str) Set the encoding of the terminal. See the 'encoding'
command for valid encodings.
AF (str) Change character foreground color in an ANSI conform
way. This capability will almost always be set to
'\E[3%dm' ('\E[3%p1%dm' on terminfo machines).
AB (str) Same as 'AF', but change background color.
AX (bool) Does understand ANSI set default fg/bg color (\E[39m /
\E[49m).
XC (str) Describe a translation of characters to strings
depending on the current font. More details follow in
the next section.
XT (bool) Terminal understands special xterm sequences (OSC, mouse
tracking).
C8 (bool) Terminal needs bold to display high-intensity colors
(e.g. Eterm).
TF (bool) Add missing capabilities to the termcap/info entry. (Set
by default).

Screen has a powerful mechanism to translate characters to arbitrary
strings depending on the current font and terminal type. Use this
feature if you want to work with a common standard character set (say
ISO8851-latin1) even on terminals that scatter the more unusual
characters over several national language font pages.
Syntax:
XC=<charset-mapping>{,,<charset-mapping>}
<charset-mapping> := <designator><template>{,<mapping>}
<mapping> := <char-to-be-mapped><template-arg>
The things in braces may be repeated any number of times.
A <charset-mapping> tells screen how to map characters in font
<designator> ('B': Ascii, 'A': UK, 'K': German, etc.) to strings.
Every <mapping> describes to what string a single character will be
translated. A template mechanism is used, as most of the time the
codes have a lot in common (for example strings to switch to and from
another charset). Each occurrence of '%' in <template> gets
substituted with the <template-arg> specified together with the
character. If your strings are not similar at all, then use '%' as a
template and place the full string in <template-arg>. A quoting
mechanism was added to make it possible to use a real '%'. The '\'
character quotes the special characters '\', '%', and ','.
Here is an example:
termcap hp700 'XC=B\E(K%\E(B,\304[,\326\\\\,\334]'
This tells screen how to translate ISOlatin1 (charset 'B') upper case
umlaut characters on a hp700 terminal that has a German charset.
'\304' gets translated to '\E(K[\E(B' and so on. Note that this line
gets parsed *three* times before the internal lookup table is built,
therefore a lot of quoting is needed to create a single '\'.
Another extension was added to allow more emulation: If a mapping
translates the unquoted '%' char, it will be sent to the terminal
whenever screen switches to the corresponding <designator>. In this
special case the template is assumed to be just '%' because the
charset switch sequence and the character mappings normally haven't
much in common.
This example shows one use of the extension:
termcap xterm 'XC=K%,%\E(B,[\304,\\\\\326,]\334'
Here, a part of the German ('K') charset is emulated on an xterm. If
screen has to change to the 'K' charset, '\E(B' will be sent to the
terminal, i.e. the ASCII charset is used instead. The template is
just '%', so the mapping is straightforward: '[' to '\304', '\' to
'\326', and ']' to '\334'.

Originally created by Oliver Laumann. For a long time maintained and
developed by Juergen Weigert, Michael Schroeder, Micah Cowan and
Sadrul Habib Chowdhury. Since 2015 maintained and developed by
Amadeusz Slawinski <amade@asmblr.net> and Alexander Naumov
<alexander_naumov@opensuse.org>.

Copyright (c) 2018
Alexander Naumov <alexander_naumov@opensuse.org>
Amadeusz Slawinski <amade@asmblr.net>
Copyright (c) 2015-2017
Juergen Weigert <jnweiger@immd4.informatik.uni-erlangen.de>
Alexander Naumov <alexander_naumov@opensuse.org>
Amadeusz Slawinski <amade@asmblr.net>
Copyright (c) 2010-2015
Juergen Weigert <jnweiger@immd4.informatik.uni-erlangen.de>
Sadrul Habib Chowdhury <sadrul@users.sourceforge.net>
Copyright (c) 2008, 2009
Juergen Weigert <jnweiger@immd4.informatik.uni-erlangen.de>
Michael Schroeder <mlschroe@immd4.informatik.uni-erlangen.de>
Micah Cowan <micah@cowan.name>
Sadrul Habib Chowdhury <sadrul@users.sourceforge.net>
Copyright (C) 1993-2003
Juergen Weigert <jnweiger@immd4.informatik.uni-erlangen.de>
Michael Schroeder <mlschroe@immd4.informatik.uni-erlangen.de>
Copyright (C) 1987 Oliver Laumann
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program (see the file COPYING); if not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA

This is version 4.3.1. Its roots are a merge of a custom version
2.3PR7 by Wayne Davison and several enhancements to Oliver Laumann's
version 2.0. Note that all versions numbered 2.x are copyright by
Oliver Laumann.

The latest official release of screen available via anonymous ftp
from ftp.gnu.org/gnu/screen/ or any other GNU distribution site. The
home site of screen is savannah.gnu.org/projects/screen/. If you want
to help, send a note to screen-devel@gnu.org.

· `dm' (delete mode) and `xs' are not handled correctly (they are
ignored). `xn' is treated as a magic-margin indicator.
· Screen has no clue about double-high or double-wide characters.
But this is the only area where vttest is allowed to fail.
· It is not possible to change the environment variable $TERMCAP
when reattaching under a different terminal type.
· The support of terminfo based systems is very limited. Adding
extra capabilities to $TERMCAP may not have any effects.
· Screen does not make use of hardware tabs.
· Screen must be installed as set-uid with owner root on most
systems in order to be able to correctly change the owner of the
tty device file for each window. Special permission may also be
required to write the file "/etc/utmp".
· Entries in "/etc/utmp" are not removed when screen is killed with
SIGKILL. This will cause some programs (like "w" or "rwho") to
advertise that a user is logged on who really isn't.
· Screen may give a strange warning when your tty has no utmp entry.
· When the modem line was hung up, screen may not automatically
detach (or quit) unless the device driver is configured to send a
HANGUP signal. To detach a screen session use the -D or -d
command line option.
· If a password is set, the command line options -d and -D still
detach a session without asking.
· Both "breaktype" and "defbreaktype" change the break generating
method used by all terminal devices. The first should change a
window specific setting, where the latter should change only the
default for new windows.
· When attaching to a multiuser session, the user's .screenrc file
is not sourced. Each user's personal settings have to be included
in the .screenrc file from which the session is booted, or have to
be changed manually.
· A weird imagination is most useful to gain full advantage of all
the features.
· Send bug-reports, fixes, enhancements, t-shirts, money, beer &
pizza to screen-devel@gnu.org.

This page is part of the screen (screen manager) project.
Information about the project can be found at
⟨http://www.gnu.org/software/screen/⟩. If you have a bug report for
this manual page, see
⟨https://savannah.gnu.org/bugs/?func=additem&group=screen⟩. This
page was obtained from the project's upstream Git repository
⟨https://savannah.gnu.org/git/?group=screen⟩ on 2019-05-09. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2019-04-17.) If you discover any rendering problems in
this HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not part
of the original manual page), send a mail to man-pages@man7.org
4th Berkeley Distribution Feb 2017 SCREEN(1)